Composite render elements, glow on certain layer

[alexxrust]

Hello! The question will be about comping *.exr Vray render elements in After Effects CS6 on a video background. Here's how I work at the moment. I blend GI and Lighting layers using "add" blending mode and then precomp these two layers. In that precomp, I also put alpha as a separate layer on the bottom and apply "set matte" to GI and Lighting layers were I select alpha layer as a matte and set "full" to Unpremultiply those layers. Then in the main comp (with video background and precomped layers on top) I again put alpha layer at the bottom and apply "set matte" to the precomp were now I choose Alpha Channel to premultiply it.

So, by doing that I can color correct layers in unpremultiplied state in their precomp and see them in the main comp with proper antialiased edge.

BUT if I apply "Glow" effect onto the Lighting layer, it looks great in the render elements precomp (the glow goes beyond the 3d object, just as needed), but in the main comp the glow stays only on the object, because the precomp is premultiplied by the alpha.

 

 

So, I want to find out is there a way to add effects such as glow or blur which go beyond the 3d object only to certain render layers. Or maybe you could suggest a better workflow. Most likely mine isn't proper