Selector problem: Empty UL inside LI

Selector problem: Empty UL inside LI

Hi *,

i just tumbled over a problem with my filetree. I guess it's a really basic, easy-to-solve problem but I don't know what to do

An example node from the filetree goes like this:
<ul>
<li>Node 1
     <ul>
         <li>Sub Node I
          <ul></ul>
         </li>
         <li>Sub Node II
          <ul></ul>
         </li>
         <li>Sub Node III
          <ul></ul>
         </li>
     </ul>
</li>
</ul>


Unfortunately the empty ULs are "necessary" by code design (got it from a book).

Then I run the following jQuery against it:
$(document).ready(function()
{
    $('li:has(ul)')
        .click(function(event)
        {
            if(this == event.target)
            {
                if($(this).children().is(':hidden'))
                {
                    $(this)
                        .css('list-style-image', 'url(images/minus.gif)')
                        .children().show();
                }
                else
                {
                    $(this)
                        .css('list-style-image', 'url(images/plus.gif)')
                        .children().hide();
                }
            }
            return false;
        })
        .css('cursor','pointer')
        .click();
           
    $('li:not(:has(ul))')
        .css({
            'cursor': 'pointer',
            'list-style-image': 'none'
        });

        ..............
       
});


How can I get rid of the Sub Node children that have an empty UL in it?

I thought of something like
$('li:has(ul:empty)')

in an extra code block just before the $('li:not(:has(ul))') but that didn't work out:
I checked the code in http://www.woods.iki.fi/interactive-jquery-tester.html but the selector matches not only for the Sub Nodes but also for the Node (which has an UL with the Sub Nodes in it and is therefore not empty).

Does anyone of you jQuery cracks have an idea what the solution might be?

Thanks a lot in advance and best from sunny Berlin!

Fabian