Porblems with "Stand Along Login Page" in 5.1

Hi, folk!!! I've one problem ... I want to set A stand alone login page for anonymous user with no action for a that user to take on my site.
The setting
global $user;
if($user->uid == 0){
$vars['template_file'] = 'page-login';//where page-login.tpl.php is my custom login page template
break;
}
return $vars;
at the
function _phptemplate_variables() in template.php file is no working! :(
...
Please, tell me how can i correct use "template_file" for this goal
Thanks advance