Question about 3d-like shapes.

Hello,

I am trying to do a diagram which looks like this:

http://developer.apple.com/mac/library/documentation/cocoa/conceptual/CocoaFundamentals/Art/systemlayers3.jpg

But I am not able to do the 3d-like shapes correctly. I've know there is a shape which looks like this in the inspector, but when I stretch the box, the '3d effect' also stretch, which kind of looks weird when boxes are of different size.

Is there anyway this effect can be achieve easily ?

Thanks,
Ben.