Sorry, I somehow missed this thread. I tested this on a simple scene and it seems to be working as expected.
I am saving to 32-bit EXR. With 16-bits I was never able to get the correct lighting (the highlights looked too dark).
Added all CShading_SourceColor and CShading_RawComponent render elements (diffuse, reflect, refract, in this case I didn't need translucency or opacity).
Then in Photoshop:
[CShading_Raw_diffuse x CShading_SourceColor_diffuse] + [CShading_Raw_reflect x CShading_SourceColor_reflect] + [CShading_Raw_refract x CShading_SourceColor_refract]