wp_nav and drop down menu and css sprite problem

im using the jquery for the drop down menu from this site: link here
and i used the css that comes with it..
my function.php for my menu looks like this:

function add_header() { ?>
		<div id="smoothmenu1" class="ddsmoothmenu">	

<ul>
<li><a href="#">Book Now</a></li>
<li><a href="#">Our Resorts</a></li>
				<?php wp_nav_menu( array('menu' => 'Our Resort','container' => 'false')); ?>

<li><a href="#">Activities</a></li>
<li><a href="#">Leisure Packages</a></li>
<li><a href="#">Event Packages</a></li>
</ul>
		</div>
<?php }
add_action('thematic_header','add_header');

But my sub nav/ sub menu is still using the ul li style instead of the ul li ul li.. i tried changing it and putting !important but the sub nav is still showing beside my menu instead of vertically dropping down. please help:)

thanx