User menu on 404 pages

Question

On 404 pages, no user menu is displayed.

I have tryed to use the 404 Navigation module but it does not help.

I also tried this code in template.php, but it doesn't work.

function bartik_user_menu() {
   $items['page-not-found'] = array(
     'title' => '',
     'page callback' => 'bartik_page_not_found',
     'access callback' => TRUE,
   );
   return $items;
 }

 function bartik_page_not_found() {
   drupal_set_title('Page not found');
   $cust_err = "";
   $cust_err = $cust_err . "The requested page " . request_uri() . " could not be found";
   return $cust_err;
 }