Index: includes/module.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/module.inc,v
retrieving revision 1.184
diff -u -p -r1.184 module.inc
--- includes/module.inc	3 Mar 2010 07:38:08 -0000	1.184
+++ includes/module.inc	25 Mar 2010 02:21:02 -0000
@@ -682,10 +682,11 @@ function module_invoke() {
   $module = $args[0];
   $hook = $args[1];
   unset($args[0], $args[1]);
-  if (module_hook($module, $hook)) {
+  if (module_hook($module, $hook) || ($hook_info = module_hook_info()) && isset($hook_info[$hook]['group']) && module_load_include('inc', $module, $module . '.' . $hook_info[$hook]['group']) && module_hook($module, $hook)) {
     return call_user_func_array($module . '_' . $hook, $args);
   }
 }
+
 /**
  * Invoke a hook in all enabled modules that implement it.
  *