FIVe3D reflection/gradient effect

I was wondering if anyone who had a chance to play with FIVe3D library could help me out to create a reflection of the rounder corners rectangle. I realized thet there in no beginGradientFill method in Graphics3D and the gradientHorizontalPlain creates a basic rectangle without rounded corners. Also, I doesn’t look like I can use masks in 3D (at least I failed trying it).

All I could do is just create a semi-transparent rectangle under, but with no reflection (fading out) effect:

http://www.shunko.com/temp/3d/zuki.html

I would appreciate if someone could point me in a right direction here. Thanks!