Index: uc_worldpay.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/uc_worldpay/uc_worldpay.module,v
retrieving revision 1.5
diff -u -p -r1.5 uc_worldpay.module
--- uc_worldpay.module	28 Oct 2009 23:51:07 -0000	1.5
+++ uc_worldpay.module	29 Oct 2009 23:34:38 -0000
@@ -259,10 +259,13 @@ function uc_worldpay_form_alter(&$form, 
           '#value' => $value,
         );
       }
-
-      $test_server = variable_get('uc_worldpay_test_url', 'https://select-test.wp3.rbsworldpay.com/wcc/purchase');
-      $live_server = variable_get('uc_worldpay_live_url', 'https://secure.wp3.rbsworldpay.com/wcc/purchase');
-      $form['#action'] = (variable_get('uc_worldpay_test', TRUE)) ? $test_server : $live_server;
+      
+      if ($form_state['post']['op'] != t('Back')) {
+        $test_server = variable_get('uc_worldpay_test_url', 'https://select-test.wp3.rbsworldpay.com/wcc/purchase');
+        $live_server = variable_get('uc_worldpay_live_url', 'https://secure.wp3.rbsworldpay.com/wcc/purchase');
+        $form['#redirect'] = (variable_get('uc_worldpay_test', TRUE)) ? $test_server : $live_server;
+      }
+      
       $form['submit'] = array(
         '#type' => 'submit',
         '#name' => '',