[wp-hackers] wp_enqueue_script does not load admin-forms in plugin page

[Malaiac]

I guess the support forum won't be of any help here
( http://wordpress.org/support/topic/200944?replies=1 )

I have a plugin page ...
/wp-admin/admin.php?page=plugin.php

in plugin.php :
$title = __('My plugin page','plugin');
$parent_file = 'plugin.php';
wp_enqueue_script('admin-forms');
require_once('admin-header.php');

And still got no forms.js loading in the header...
should be this one, like in edit.php :
<script type='text/javascript'
src='http://www.mydomain.com/wp-admin/js/forms.js?ver=20080401'></script>

anyone got a clue why ?