According to eovia's dialog this demo is only limited by about 4 things and save import or export should work. fbx didn't work for me nor bvh, but I bet it is a demo thing. I don't think it is supposed to do that tho or they would have said. I doubt they would let major bugs like that go.Does make it hard to evaluate tho. Demos can be a pain. Here is the list of limited demo features attached.

No need to think outside the box....
    Just make it invisible.