YafRay - Sticker on a glass bottle problem.

First of all, thanks for even clicking on this link. I appreciate any help.
I feel like a noob again…

Download AlphaGlass.zip 108kb (it is DATA packed, alpha image included)

No problem with Blender Internal render. This is concerning Yafray.

I am trying to create a Decal (or sticker) on a bottle in Yafray. It almost works. If you look at the picture above, you can see that part of the decal is transparent. You can download the blend file (AlphaGlass.zip) and give it a try.