diff --git a/uc_attributes_in_cart.module b/uc_attributes_in_cart.module
index 1690e5c..1fcd204 100644
--- a/uc_attributes_in_cart.module
+++ b/uc_attributes_in_cart.module
@@ -114,9 +114,7 @@ function uc_attributes_in_cart_form_alter(&$form, &$form_state, $form_id) {
     uc_attributes_in_cart_display_attributes_forms($form['items']);
 
     // Make the 'update cart' and 'checkout' buttons process our submit function.
-    $form['#submit'][] = 'uc_attributes_in_cart_cart_view_form_submit';
-    $form['update']['#submit'][] = 'uc_attributes_in_cart_cart_view_form_submit';
-    $form['checkout']['#submit'][] = 'uc_attributes_in_cart_cart_view_form_submit';
+    $form['#submit'] = array_merge(array('uc_attributes_in_cart_cart_view_form_submit'), (array) $form['#submit']);
   }
 }