Vray Toon Material and Mapped Surfaces

I’m starting to use the toon materials in Vray successfully but have run into problems when trying to add a mapped, non-toon material to the scene. When rendered, the transparency map for the surface (a tree in this instance) renders as solid black fill where it overlaps with the toon materials. Any help is appreciated.

I think it’s a known bug.
Actually the toon material doesn’t handle transparency in the right way.
This has to be solved in the latest version. Did you have the upgrade?