Use baked shadows on separate mesh? I have an architectural model with a shadow map on a separate mesh, that is positioned very close on top of the first one. The shadow map is only for two rooms of the interior and the uv layout is different, so i can't just put the texture on the first mesh. I tried setting it to "Ambient" in Blender Internal and went through different blend modes, but it doesn't work. How do i set this up correctly (Internal or Cycles)?
I have an idea, that you can use compositing to achieve this task:

I created 2 render layers, one for color (I make them solid using Emission node):



And this for the baked shadows (and objects with real shadows are holdout, to make a transparent on their place):



And multiply shadows with color in compositing nodes this way: