Vertex color as radiosity emiter?

It’s late night right now and I’m too tired to dig this forum some more…

So, my goal is to UV map half of a sphere with an hemispherical sky photo, bake texture to vertex color and use it via radiosity calculation to make nice light for real time architectural presentation.
After few tests it seems to be imposible, but maybe I’m just missing sth.

  1. can’t bake UV mapped texture to vertex color, it actually works, but VCol looks like made with texture using coordinates different than UV. How to correct it? Python script?
  2. Is there way to trick Blender into using VCol as an emiter for radiosity calculation? (maybe a script that splits emiter mesh into faces and creates for them a bunch of materials with colors based on VCol - one per a new object)