<div id="menubar">
<ul class="menus">
<li class="..."><a href="http://.../">Home</a></li>
<li class="..."><a href="http://.../">菜單項1</a></li>
<li class="..."><a href="http://.../">菜單項2</a></li>
<li class="..."><a href="http://.../">菜單項3</a></li>
...
</ul>
</div>

<?php
echo str_replace("</ul></div>", "", ereg_replace("<div[^>]*><ul[^>]*>", "", wp_nav_menu(array('theme_location' => 'primary', 'echo' => false)) ));
?>