if / else custom menu in 3.0

I’m adding a custom menu in my header. The new fuction in WP 3.0 that lets admins add a custom menu to the theme.

(wp_nav_menu)

The code I add works fine when I create a menu in the dashboard, but when I remove the menu it showes the default setup with a container etc. How can I make this a list-style?

here is my code:

<?php wp_nav_menu( array( 'container' => '', 'depth=1&title_li=','menu_id' => 'navmenu-h' , 'theme_location' => 'primary' ) ); ?>

The code above gives this result when I have added a custom menu in the dashboard:

<li id="menu-item-195" class="menu-item menu-item-type-custom current-menu-item current_page_item menu-item-home menu-item-195"><a href="http://comain.com/">Home</a></li> 

<li id="menu-item-196" class="menu-item menu-item-type-post_type menu-item-196"><a href="http://domain.com/?page_id=72">Guestbook</a></li> 

<li id="menu-item-197" class="menu-item menu-item-type-post_type menu-item-197"><a href="http://domain.com/?page_id=174">Testpage</a></li>

When I delete the custom menu from the dashboard it gives me a defaul output like this:

<div class="menu">
<ul>
<li class="page_item page-item-72"><a href="http://domain.com/?page_id=72" title="Hyttebok">Guestbook</a></li>

<li class="page_item page-item-174"><a href="http://domain.com/?page_id=174" title="testpage1">Testpage</a></li>
</ul>
</div>

My main wish is to not show anything if the admin havent created a menu. easy: if menu = show menu – else = dont show anything.

Anyone know how to solve this? I have tryed to use the ‘fallback_cb’ but it diesnt seem to react like it should