Matte Surface with VrayLightRect

[scorpes]

Hey guy's

I have problems making a proper matte surface, I get bounce light from the VrayLightRect on my matte surface and I don't want this for compositing. I think it's because the environment light is bouncing via the VrayLightRect on the matte surface. Is it possible to disable the VrayLightRect for bouncing GI?
Below you can see what the problem is:

[tashko.zashev]

In other to get a clear alpha only with the shadows, uncheck “receive GI” for the matte surface in vray object properties or material wrapper. Note that the shadow will be darker (without Gi on it). For better control you could render the shadow in separate pass with hidden Sphere.
I hope this helps you.