diff --git a/CRM/Twingle/Form/Profile.php b/CRM/Twingle/Form/Profile.php
index 975a198..718a0e9 100644
--- a/CRM/Twingle/Form/Profile.php
+++ b/CRM/Twingle/Form/Profile.php
@@ -129,6 +129,28 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
       TRUE // is required
     );
 
+    $this->add(
+      'select',
+      'gender_male',
+      E::ts('Gender option for submitted value "male"'),
+      $this->getGenderOptions(),
+      TRUE
+    );
+    $this->add(
+      'select',
+      'gender_female',
+      E::ts('Gender option for submitted value "female"'),
+      $this->getGenderOptions(),
+      TRUE
+    );
+    $this->add(
+      'select',
+      'gender_other',
+      E::ts('Gender option for submitted value "other"'),
+      $this->getGenderOptions(),
+      TRUE
+    );
+
     $payment_instruments = CRM_Twingle_Profile::paymentInstruments();
     $this->assign('payment_instruments', $payment_instruments);
     foreach ($payment_instruments as $pi_name => $pi_label) {
@@ -141,6 +163,16 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
       );
     }
 
+    if (CRM_Twingle_Submission::civiSepaEnabled()) {
+      $this->add(
+        'select',
+        'sepa_creditor_id',
+        E::ts('CiviSEPA creditor'),
+        $this->getSepaCreditors(),
+        TRUE
+      );
+    }
+
     $this->add(
       'select', // field type
       'newsletter_groups', // field name
@@ -282,17 +314,42 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
    * Retrieves campaigns present within the system as options for select form
    * elements.
    */
-  public function getCampaigns() {
-    $campaigns = array('' => E::ts("no campaign"));
-    $query = civicrm_api3('Campaign', 'get', array(
+  public function getGenderOptions() {
+    $genders = array();
+    $query = civicrm_api3('OptionValue', 'get', array(
+      'option_group_id' => 'gender',
       'is_active'    => 1,
       'option.limit' => 0,
-      'return'       => 'id,title'
+      'return' => array(
+        'value',
+        'label',
+      ),
     ));
-    foreach ($query['values'] as $campaign) {
-      $campaigns[$campaign['id']] = $campaign['title'];
+    foreach ($query['values'] as $gender) {
+      $genders[$gender['value']] = $gender['label'];
     }
-    return $campaigns;
+    return $genders;
+  }
+
+  /**
+   * Retrieves CiviSEPA creditors as options for select form elements.
+   *
+   * @return array
+   * @throws \CiviCRM_API3_Exception
+   */
+  public function getSepaCreditors() {
+    $creditors = array();
+
+    if (CRM_Twingle_Submission::civiSepaEnabled()) {
+      $result = civicrm_api3('SepaCreditor', 'get', array(
+        'option.limit' => 0,
+      ));
+      foreach ($result['values'] as $sepa_creditor) {
+        $creditors[$sepa_creditor['id']] = $sepa_creditor['name'];
+      }
+    }
+
+    return $creditors;
   }
 
   /**
@@ -309,7 +366,21 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
         'return'          => 'value,label'
       ));
       foreach ($query['values'] as $payment_instrument) {
-        self::$_paymentInstruments[$payment_instrument['value']] = $payment_instrument['label'];
+        // Do not include CiviSEPA payment instruments, but add a SEPA option if
+        // enabled.
+        if (
+          CRM_Twingle_Submission::civiSepaEnabled()
+          && CRM_Sepa_Logic_Settings::isSDD(array(
+            'payment_instrument_id' => $payment_instrument['value'],
+          ))
+        ) {
+          if (!isset(self::$_paymentInstruments['sepa'])) {
+            self::$_paymentInstruments['sepa'] = E::ts('CiviSEPA');
+          }
+        }
+        else {
+          self::$_paymentInstruments[$payment_instrument['value']] = $payment_instrument['label'];
+        }
       }
     }
     return self::$_paymentInstruments;
@@ -338,7 +409,23 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
       }
     }
     else {
-      $groups[''] = E::ts('No newsletter groups available');
+      $groups[''] = E::ts('No mailing lists available');
+    }
+    return $groups;
+  }
+
+  /**
+   * Retrieves active groups as options for select form elements.
+   */
+  public function getGroups() {
+    $groups = array();
+    $query = civicrm_api3('Group', 'get', array(
+      'is_active' => 1,
+      'option.limit'   => 0,
+      'return'         => 'id,name'
+    ));
+    foreach ($query['values'] as $group) {
+      $groups[$group['id']] = $group['name'];
     }
     return $groups;
   }
@@ -348,27 +435,7 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
    * options for select form elements.
    */
   public function getPostinfoGroups() {
-    $groups = array();
-    $group_types = civicrm_api3('OptionValue', 'get', array(
-      'option_group_id' => 'group_type',
-      'name' => CRM_Twingle_Submission::GROUP_TYPE_POSTINFO,
-    ));
-    if ($group_types['count'] > 0) {
-      $group_type = reset($group_types['values']);
-      $query = civicrm_api3('Group', 'get', array(
-        'is_active' => 1,
-        'group_type' => array('LIKE' => '%' . CRM_Utils_Array::implodePadded($group_type['value']) . '%'),
-        'option.limit'   => 0,
-        'return'         => 'id,name'
-      ));
-      foreach ($query['values'] as $group) {
-        $groups[$group['id']] = $group['name'];
-      }
-    }
-    else {
-      $groups[''] = E::ts('No postal mailing groups available');
-    }
-    return $groups;
+    return $this->getGroups();
   }
 
   /**
@@ -376,27 +443,7 @@ class CRM_Twingle_Form_Profile extends CRM_Core_Form {
    * system as options for select form elements.
    */
   public function getDonationReceiptGroups() {
-    $groups = array();
-    $group_types = civicrm_api3('OptionValue', 'get', array(
-      'option_group_id' => 'group_type',
-      'name' => CRM_Twingle_Submission::GROUP_TYPE_DONATION_RECEIPT,
-    ));
-    if ($group_types['count'] > 0) {
-      $group_type = reset($group_types['values']);
-      $query = civicrm_api3('Group', 'get', array(
-        'is_active' => 1,
-        'group_type' => array('LIKE' => '%' . CRM_Utils_Array::implodePadded($group_type['value']) . '%'),
-        'option.limit'   => 0,
-        'return'         => 'id,name'
-      ));
-      foreach ($query['values'] as $group) {
-        $groups[$group['id']] = $group['name'];
-      }
-    }
-    else {
-      $groups[''] = E::ts('No donation receipt groups available');
-    }
-    return $groups;
+    return $this->getGroups();
   }
 
 }
diff --git a/CRM/Twingle/Profile.php b/CRM/Twingle/Profile.php
index ff031e2..aa6bd0f 100644
--- a/CRM/Twingle/Profile.php
+++ b/CRM/Twingle/Profile.php
@@ -180,6 +180,10 @@ class CRM_Twingle_Profile {
       'pi_paydirekt',
       'pi_applepay',
       'pi_googlepay',
+      'sepa_creditor_id',
+      'gender_male',
+      'gender_female',
+      'gender_other',
       'newsletter_groups',
       'postinfo_groups',
       'donation_receipt_groups'
@@ -221,19 +225,23 @@ class CRM_Twingle_Profile {
       'location_type_id'  => CRM_Twingle_Submission::LOCATION_TYPE_ID_WORK,
       'financial_type_id' => 1, // "Donation"
       'pi_banktransfer' => 5, // "EFT"
-      'pi_debit_manual' => '', // TODO: SEPA
+      'pi_debit_manual' => NULL,
       'pi_debit_automatic' => 3, // Debit
       'pi_creditcard' => 1, // "Credit Card"
-      'pi_mobilephone_germany' => '',
-      'pi_paypal' => '',
-      'pi_sofortueberweisung' => '',
-      'pi_amazonpay' => '',
-      'pi_paydirekt' => '',
-      'pi_applepay' => '',
-      'pi_googlepay' => '',
-      'newsletter_groups' => '',
-      'postinfo_groups' => '',
-      'donation_receipt_groups' => '',
+      'pi_mobilephone_germany' => NULL,
+      'pi_paypal' => NULL,
+      'pi_sofortueberweisung' => NULL,
+      'pi_amazonpay' => NULL,
+      'pi_paydirekt' => NULL,
+      'pi_applepay' => NULL,
+      'pi_googlepay' => NULL,
+      'sepa_creditor_id' => NULL,
+      'gender_male' => 2,
+      'gender_female' => 1,
+      'gender_other' => 3,
+      'newsletter_groups' => NULL,
+      'postinfo_groups' => NULL,
+      'donation_receipt_groups' => NULL,
     ));
   }
 
diff --git a/CRM/Twingle/Submission.php b/CRM/Twingle/Submission.php
index 06db85f..5356139 100644
--- a/CRM/Twingle/Submission.php
+++ b/CRM/Twingle/Submission.php
@@ -27,16 +27,6 @@ class CRM_Twingle_Submission {
    */
   const GROUP_TYPE_NEWSLETTER = 'Mailing List';
 
-  /**
-   * The option value name of the group type for postal mailing subscribers.
-   */
-  const GROUP_TYPE_POSTINFO = ''; // TODO.
-
-  /**
-   * The option value name of the group type for donation receipt requesters.
-   */
-  const GROUP_TYPE_DONATION_RECEIPT = ''; // TODO.
-
   /**
    * The default ID of the "Employer of" relationship type.
    */
@@ -100,7 +90,7 @@ class CRM_Twingle_Submission {
 
     // Get the gender ID defined within the profile, or return an error if none
     // matches (i.e. an unknown gender was submitted).
-    if (!$gender_id = $profile->getAttribute('gender_' . $params['user_gender'])) {
+    if (!empty($params['user_gender']) && !$gender_id = $profile->getAttribute('gender_' . $params['user_gender'])) {
       throw new CiviCRM_API3_Exception(
         E::ts('Gender could not be matched to existing gender.'),
         'invalid_format'
@@ -249,4 +239,60 @@ class CRM_Twingle_Submission {
     }
   }
 
+  /**
+   * Check whether the CiviSEPA extension is installed and CiviSEPA
+   * functionality is activated within the Twingle extension settings.
+   *
+   * @return bool
+   * @throws \CiviCRM_API3_Exception
+   */
+  public static function civiSepaEnabled() {
+    $sepa_extension = civicrm_api3('Extension', 'get', array(
+      'full_name' => 'org.project60.sepa',
+      'is_active' => 1,
+    ));
+    return
+      CRM_Core_BAO_Setting::getItem(
+        'de.systopia.twingle',
+        'twingle_use_sepa'
+      )
+      && $sepa_extension['count'];
+  }
+
+  /**
+   * Retrieves recurring contribution frequency attributes for a given donation
+   * rhythm parameter value, according to a static mapping.
+   *
+   * @param string $donation_rhythm
+   *   The submitted "donation_rhythm" paramter according to the API action
+   *   specification.
+   *
+   * @return array
+   *   An array with "frequency_unit" and "frequency_interval" keys, to be added
+   *   to contribution parameter arrays.
+   */
+  public static function getFrequencyMapping($donation_rhythm) {
+    $mapping = array(
+      'halfyearly' => array(
+        'frequency_unit' => 'month',
+        'frequency_interval' => 6,
+      ),
+      'quarterly' => array(
+        'frequency_unit' => 'month',
+        'frequency_interval' => 3,
+      ),
+      'yearly' => array(
+        'frequency_unit' => 'year',
+        'frequency_interval' => 1,
+      ),
+      'monthly' => array(
+        'frequency_unit' => 'month',
+        'frequency_interval' => 1,
+      ),
+      'one_time' => array(),
+    );
+
+    return $mapping[$donation_rhythm];
+  }
+
 }
diff --git a/api/v3/TwingleDonation/Submit.php b/api/v3/TwingleDonation/Submit.php
index c26faf1..cfb8ba0 100644
--- a/api/v3/TwingleDonation/Submit.php
+++ b/api/v3/TwingleDonation/Submit.php
@@ -251,7 +251,10 @@ function civicrm_api3_twingle_donation_Submit($params) {
     $existing_contribution = civicrm_api3('Contribution', 'get', array(
       'trxn_id' => $params['trx_id']
     ));
-    if ($existing_contribution['count'] > 0) {
+    $existing_contribution_recur = civicrm_api3('ContributionRecur', 'get', array(
+      'trxn_id' => $params['trx_id']
+    ));
+    if ($existing_contribution['count'] > 0 || $existing_contribution_recur['count'] > 0) {
       throw new CiviCRM_API3_Exception(
         E::ts('Contribution with the given transaction ID already exists.'),
         'api_error'
@@ -298,19 +301,17 @@ function civicrm_api3_twingle_donation_Submit($params) {
       // Exclude address for now when retrieving/creating the individual contact
       // and an organisation is given, as we are checking organisation address
       // first and share it with the individual.
-      if (!empty($params['organization_name'])) {
-        $submitted_address = array();
-        foreach (array(
-                   'street_address',
-                   'postal_code',
-                   'city',
-                   'country',
-                   'location_type_id',
-                 ) as $address_component) {
-          if (!empty($params[$address_component])) {
-            $submitted_address[$address_component] = $params[$address_component];
-            unset($params[$address_component]);
-          }
+      $submitted_address = array();
+      foreach (array(
+                 'street_address',
+                 'postal_code',
+                 'city',
+                 'country',
+                 'location_type_id',
+               ) as $address_component) {
+        if (!empty($params[$address_component])) {
+          $submitted_address[$address_component] = $params[$address_component];
+          unset($params[$address_component]);
         }
       }
 
@@ -324,6 +325,7 @@ function civicrm_api3_twingle_donation_Submit($params) {
                  'user_birthdate' => 'birth_date',
                  'user_email' => 'email',
                  'user_telephone' => 'phone',
+                 'user_title' => 'formal_title',
                ) as $contact_param => $contact_component) {
         if (!empty($params[$contact_param])) {
           $contact_data[$contact_component] = $params[$contact_param];
@@ -354,7 +356,9 @@ function civicrm_api3_twingle_donation_Submit($params) {
           'organization_name' => $params['organization_name'],
         );
         if (!empty($submitted_address)) {
-          $params += $submitted_address;
+          $organisation_data += $submitted_address;
+          // Always use WORK address for organisation address.
+          $organisation_data['location_type_id'] = CRM_Twingle_Submission::LOCATION_TYPE_ID_WORK;
         }
         if (!$organisation_id = CRM_Twingle_Submission::getContact(
           'Organization',
@@ -366,16 +370,18 @@ function civicrm_api3_twingle_donation_Submit($params) {
           );
         }
       }
+      // Share organisation address as WORK address with individual contact.
       $address_shared = (
         isset($organisation_id)
         && CRM_Twingle_Submission::shareWorkAddress(
           $contact_id,
           $organisation_id,
-          $params['location_type_id']
+          CRM_Twingle_Submission::LOCATION_TYPE_ID_WORK
         )
       );
 
-      // Address is not shared, use submitted address.
+      // Address is not shared, use submitted address with configured location
+      // type.
       if (!$address_shared && !empty($submitted_address)) {
         $submitted_address['contact_id'] = $contact_id;
         civicrm_api3('Address', 'create', $submitted_address);
@@ -387,45 +393,88 @@ function civicrm_api3_twingle_donation_Submit($params) {
       }
     }
 
-    // TODO: contact into newsletter, postinfo and donation_receipt groups.
+    // If requested, add contact to newsletter groups defined in the profile.
+    if (!empty($params['newsletter']) && !empty($groups = $profile->getAttribute('newsletter_groups'))) {
+      foreach ($groups as $group_id) {
+        civicrm_api3('GroupContact', 'create', array(
+          'group_id' => $group_id,
+          'contact_id' => $contact_id,
+        ));
+      }
+    }
 
-    // Create contribution or SEPA mandate.
+    // If requested, add contact to postinfo groups defined in the profile.
+    if (!empty($params['postinfo']) && !empty($groups = $profile->getAttribute('postinfo_groups'))) {
+      foreach ($groups as $group_id) {
+        civicrm_api3('GroupContact', 'create', array(
+          'group_id' => $group_id,
+          'contact_id' => $contact_id,
+        ));
+      }
+    }
+
+    // If requested, add contact to donation_receipt groups defined in the
+    // profile.
+    if (!empty($params['donation_receipt']) && !empty($groups = $profile->getAttribute('donation_receipt_groups'))) {
+      foreach ($groups as $group_id) {
+        civicrm_api3('GroupContact', 'create', array(
+          'group_id' => $group_id,
+          'contact_id' => $contact_id,
+        ));
+      }
+    }
+
+    // Create contribution or SEPA mandate. Those attributes are valid for both,
+    // single and recurring contributions.
     $contribution_data = array(
       'contact_id' => (isset($organisation_id) ? $organisation_id : $contact_id),
       'currency' => $params['currency'],
       'trxn_id' => $params['trx_id'],
       'financial_type_id' => $profile->getAttribute('financial_type_id'),
       'payment_instrument_id' => $params['payment_instrument_id'],
-      'amount' => $params['amount'],
-      'total_amount' => $params['amount'],
+      'amount' => $params['amount'] / 100,
+      'total_amount' => $params['amount'] / 100,
     );
     if (!empty($params['purpose'])) {
       $contribution_data['note'] = $params['purpose'];
     }
 
-    $sepa_extension = civicrm_api3('Extension', 'get', array(
-      'full_name' => 'org.project60.sepa',
-      'is_active' => 1,
-    ));
     if (
-      CRM_Core_BAO_Setting::getItem(
-        'de.systopia.twingle',
-        'twingle_use_sepa'
-      )
-      && $sepa_extension['count']
-      && CRM_Sepa_Logic_Settings::isSDD($contribution_data)
+      CRM_Twingle_Submission::civiSepaEnabled()
+      && $contribution_data['payment_instrument_id'] == 'sepa'
     ) {
       // If CiviSEPA is installed and the financial type is a CiviSEPA-one,
       // create SEPA mandate (and recurring contribution, using "createfull" API
       // action).
-      $mandate_data = $contribution_data + array(
+      foreach (array(
+        'debit_iban',
+        'debit_bic',
+               ) as $sepa_attribute) {
+        if (empty($params[$sepa_attribute])) {
+          throw new CiviCRM_API3_Exception(
+            E::ts('Missing attribute %1 for SEPA mandate', array(
+              1 => $sepa_attribute,
+            )),
+            'invalid_format'
+          );
+        }
+      }
+
+      $mandate_data =
+        $contribution_data
+        // Add CiviSEPA mandate attributes.
+        + array(
           'type' => ($params['donation_rhythm'] == 'one_time' ? 'OOFF' : 'RCUR'),
           'iban' => $params['debit_iban'],
           'bic' => $params['debit_bic'],
           'reference' => $params['debit_mandate_reference'],
           'date' => $params['confirmed_at'],
           'creditor_id' => $profile->getAttribute('sepa_creditor_id'),
-        );
+        )
+      // Add frequency unit and interval from static mapping.
+      + CRM_Twingle_Submission::getFrequencyMapping($params['donation_rhythm']);
+      // Let CiviSEPA set the correct payment instrument.
+      unset($mandate_data['payment_instrument_id']);
       $mandate = civicrm_api3('SepaMandate', 'createfull', $mandate_data);
       if ($mandate['is_error']) {
         throw new CiviCRM_API3_Exception(
@@ -434,17 +483,19 @@ function civicrm_api3_twingle_donation_Submit($params) {
         );
       }
 
-      $result_values = $mandate;
+      $result_values = $mandate['values'];
     }
     else {
       // Create (recurring) contribution.
       if ($params['donation_rhythm'] != 'one_time') {
         // Create recurring contribution first.
-        $contribution_recur_data = $contribution_data + array(
-            'frequency_interval' => '', // TODO
+        $contribution_recur_data =
+          $contribution_data
+          + array(
             'contribution_status_id' => 'Pending', // TODO: Or "In Progress"?
             'start_date' => $params['confirmed_at'],
-          );
+          )
+          + CRM_Twingle_Submission::getFrequencyMapping($params['donation_rhythm']);
         $contribution_recur = civicrm_api3('contributionRecur', 'create', $contribution_recur_data);
         if ($contribution_recur['is_error']) {
           throw new CiviCRM_API3_Exception(
@@ -468,7 +519,7 @@ function civicrm_api3_twingle_donation_Submit($params) {
         );
       }
 
-      $result_values = $contribution;
+      $result_values = $contribution['values'];
     }
 
     $result = civicrm_api3_create_success($result_values);
diff --git a/templates/CRM/Twingle/Form/Profile.tpl b/templates/CRM/Twingle/Form/Profile.tpl
index 6931fe5..62b2d8a 100644
--- a/templates/CRM/Twingle/Form/Profile.tpl
+++ b/templates/CRM/Twingle/Form/Profile.tpl
@@ -42,6 +42,26 @@
           <td class="content">{$form.financial_type_id.html}</td>
         </tr>
 
+        {if isset($form.sepa_creditor_id)}
+          <tr class="crm-section">
+            <td class="label">{$form.sepa_creditor_id.label}</td>
+            <td class="content">{$form.sepa_creditor_id.html}</td>
+          </tr>
+        {/if}
+
+        <tr class="crm-section">
+          <td class="label">{$form.gender_male.label}</td>
+          <td class="content">{$form.gender_male.html}</td>
+        </tr>
+        <tr class="crm-section">
+          <td class="label">{$form.gender_female.label}</td>
+          <td class="content">{$form.gender_female.html}</td>
+        </tr>
+        <tr class="crm-section">
+          <td class="label">{$form.gender_other.label}</td>
+          <td class="content">{$form.gender_other.html}</td>
+        </tr>
+
       </table>
 
     </fieldset>
@@ -78,8 +98,8 @@
         </tr>
 
         <tr class="crm-section">
-          <td class="label">{$form.donation_receipts_groups.label}</td>
-          <td class="content">{$form.donation_receipts_groups.html}</td>
+          <td class="label">{$form.donation_receipt_groups.label}</td>
+          <td class="content">{$form.donation_receipt_groups.html}</td>
         </tr>
 
       </table>