I am trying to do the same thing.
Did you solve it?
my code is as follows and shows the top menu and dispalys the content of the sub menu but not a submenu tab.
`
// mt_add_pages() is the sink function for the ‘admin_menu’ hook
function mt_add_pages()
{
// Add a new top-level menu:
// The first parameter is the Page name(Site Help), second is the Menu name(Help)
//and the number(5) is the user level that gets access
add_menu_page(‘Site Help’, ‘Help’, 5, __FILE__, ‘mt_toplevel_page’);
add_submenu_page(‘__FILE__’,’Site Help’,’Authors’,5,__FILE__,’submenu_1′);
}
// mt_toplevel_page() displays the page content for the custom Test Toplevel menu
function mt_toplevel_page() {
echo ‘
<div class=”wrap”>
<h2>Site Help</h2>
//content
</div>
‘;
}
function submenu_1(){
echo “hello World”;
}
// Insert the mt_add_pages() sink into the plugin hook list for ‘admin_menu’
add_action(‘admin_menu’, ‘mt_add_pages’);
?>