Extracting sky but retain reflections in alpha channel

[olen]

I am using the vray for sketchup 7 pro plugin for rendering some interiors with large expanses of glass. I want to extract the sky in the windows to put in an actual photo background but retain the reflections.

 

When saving the render views, I get the alpha channel to take out the entire window, but this doesn't let me isolate the reflections. I was curious if there was a way to save different alpha channels for just the reflections so i could put that over the true exterior image without having to go in myself in photoshop to do it manually.

 

Thanks

[slinley]

Can you render another version with your glass as a mirrored material then you can select this layer using your alpha and make the reflections as strong as you like.

[olen]

Thanks for the reply, but the thing is I can get the reflections as bright or strong as i want. But what I am trying to do is after rendering in vray, take it in photoshop with a file that has a layer of just the sky part of the reflection so i can take out just that and leave the reflection.

 

In the image, it would be taking just the circled areas so the reflections are not part of the entire window alpha channel.