Changing zIndex for resizable's handles

Hi,
The resizable function works great for me, but I have little problem:
the handles are overlapping everything else: if I have a floating DIV
(fake popup) above my resizable element, the handles for resizing will
overlap my DIV.
Is there a way to change this. It seems there was a zIndex option in
some previous version, but it doesn't seem to work anymore.
Can someone help?
Thanks a lot!
Thomas