Back to beauty behind glass

[MikkoK]

Hi

I'm rendering a scene of a house with big windows. I'm trying to use back to beauty render elements (or the elements individually) but all but the refraction element are totally black where the glass is. I tried to put affect all channels in glass' reflection and refraction, but it didn't help. It would be nice to control the elements in post. Any ideas how?

Thanks
Mikko

[hermit.crab]

Mind if you attach/send a simple scene, where the issue is present?