3 levels of navigation

Hi,

I’m creating a sub navigation on a page using wp_list_pages. Unfortunately, when I go to the Level 3 navigation in the sub menu, the Level 2 navigation disappears.

To illustrate, my page looks like this from a navigation point of view:

Primary Nav
Level 1 | Level 1 | Level 1

Sub Nav
Level 2
Level 2
— Level 3
— Level 3
Level 2

My wp_list_pages for the sub nav looks like this:

if($post->post_parent)
  $children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0");
  else
  $children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
  if ($children) { ?>
  <ul>
  <?php echo $children; ?>
  </ul>

Thanks in advance!

Nick