Display menu/submenu on a node with php code on drupal6

Hi,

I trying to port my site from drupal5 to drupal6. One of the main problems I'm having is that I can't find a way to display menus on nodes or blocks using php code...

On my drupal5 site I used php code like this:

$mid = 42;
print theme('menu_tree', $mid);

or (when want to show the menu relative to the node)

$localNav = _menu_get_active_trail();
if($localNav[1]) {
    print theme_menu_tree($localNav[1]);
}

But I haven't foud any way to do so... I've searched here, googled it, etc, with no luck.

Thanks in advande for any help
Cheers,
Mguel