wpmu-nelo nav menu (sub-sub-pages)

I have a site with pages, sub-pages, and sub-sub-pages.

Using wpmu-nelo, I would like the nav menu (in the header) to show the pages (which it does) and the subpages (which it does--in a drop-down list beneath each page), and also the sub-sub-pages. I can't seem to get it to do that.

If I very very carefully roll my cursor down the drop-down list of sub-pages, I can see (after changing wp_list_pages to depth=0 in header.php) that there ARE links to the sub-sub-pages (I can see the sub-sub-page in the status bar at the bottom of my browser window). They are just invisible--no text or link shows up, although the cursor does change when you manage to hit them just right.

It seems like this should be an easy CSS fix (ideally, I would like them to be indented slightly--"nested"--beneath their parent pages in the drop-down, maybe with a raquo or two--even a dash, but any solution that allows them to appear would be fine).

Any ideas?