wp_nav_menu() for second level navigation ONLY

Hello everyone,

i realize there’s been some posts about this on the forum, however i was not able to find a solid solution to what exactly i need. Basically i got a two level navigation structure.

As for the Layout the navigation however is divided into first-level only and second-level only.

wp_nav_menu() to my knowledge is only able to give a depth-parameter but not a start-depth parameter (which should be added!). I searched a lot of posts and blog posts but i am just not able to find a solid solution and i can’t see how i could be able to solve this using a custom walker class (but maybe i dont see the wood because there’s too many trees around…)

So to sum it up, i have this menu:

<ul><li>MAIN
  <ul><li>2nd</li><li>2nd</li><li>2nd</li></ul>
 </li></ul>

And i only want the SECOND LINE as an output. All codes i’ve tested only print out the MAIN title, too, or the HTML is messed up (two UL or similar).

If someone got a working solution for that i’d be very grateful!
And i really think that given todays site-structures a feature like that would be accepted very well in the standard code!

thanks in advance
sam