I tried most of the things:

When I change the material in MED only the brightness
changes in WED but not the shadows. (strange!)

When I use a skin with more than one colour nothing is
different exept the skin. (no shadows)

I made an empty template-code-game and it`s still the same.

But the strangest thing is when I load the model in
"MatsEd Material Editor" it looks great!!
Exactly as it should.

What is wrong with my Version of 3DGS????

Thank you for all your effords!