Baking only works for one texture set

Hi,

I am importing a lowpoly model from Blender into SP. SP only bakes only the maps for one texture set. The other two are empty. When I manually try to bake all maps for all texture sets, it doesn't work.

Here's a short video of my problem:

Any idea what I am missing? Also when I import an obj another texture set is the "base", e.G. the body...but then the head is missing...