[jQuery] SuperFish menu and the z-index property.

Hi,
I am using a Superfish menu in my Joomla web site. Works well enough
with my customisations.
The problem is I use a javascript Slideshow just below the menu. This
slideshow uses both the z-index and opacity property to fade images
ontop of one another.
In IE7, the superfish's submenu pops below the slideshow's image. I
can set the submenu's z-index to 99 to no avail.
It works wonder on firefox, chrome, safari though. Even when the z-
index property is not set.
If I replace my slideshow by a static image, the menu comes on top of
it nicely on IE.
I dont know what trick to use to have the menu appears above the
slideshow in IE.
Your help would be apreciated.