--- vertical_tabs.module.orig	2009-12-09 01:23:00.000000000 +0100
+++ vertical_tabs.module	2009-12-10 13:39:48.218750000 +0100
@@ -30,7 +30,9 @@ function vertical_tabs_form_alter(&$form
     vertical_tabs_remove_vertical_tabs($form);
   }
   elseif ($config) {
-    $form['#vertical_tabs'] = is_array($config) ? $config : array();
+    //respect any configuration added with hook_form_alter
+    $form['#vertical_tabs'] = isset($form['#vertical_tabs']) ? $form['#vertical_tabs'] : array();
+    $form['#vertical_tabs'] += is_array($config) ? $config : array();
     $form['#pre_render'][] = 'vertical_tabs_form_pre_render';
     //@todo Validation errors do not get JavaScript re-included.
     //$form['#cache'] = FALSE;