give ID tot menu_tree

Hello,
I'm using :

<div class="themas"><?php $menuhtml = theme_menu_tree(179);print $menuhtml;?></div>

...to show a custom made menu in Drupal 5.
Now I want to style these menu-items, so every menu-item has a unique ID, how can I arrange that?
The classes I now have are all the same:

<ul class="menu">
<li class="leaf"></li>
<li class="leaf"></li>
<li class="leaf"></li>
<li class="leaf"></li>
</ul>

I Thank you on forhand