Yeah this would make life a lot easier woudn't it?
I exported a simple box with 2 different textures to directx. Opening up the model in notepad confirmed that there are two separate texture references.
But unfortunately it seems that FPSC only references one of these, there is only one reference in the FPE file.
It would be SOOO useful if FPSC could support this. For example, a building model could contain a
tileable brick texture, which usually looks way better than a single stretched bitmap, and then use a separate texture for the windows for example. The result would be a much more detailed building than using a single stretched texture for the entire building.
And it would probably end up using less texture memory in the end anyway, since you could get away with using a smaller brick texture and just tile it.
Maybe someday....or maybe there's a secret to get this working. Maybe I'll email support with this question.