fake shadows problem

I've put a module into top6 (it's Simple Image Rotator) and, so that there isn't a white border around the rotating images, I set the "Module Class Suffix" to "padding=0px". This causes the fake shadows (shadow_right.png and shadow_left.png) to disappear. Set the module class suffix to "padding=1px" and the shadows come back. Could you advise how I could have "padding=0px" and the shadows?

Many thanks