new model problem

[Brute]

Hey guys, I have a small problem with importing models in the game. I succesfully manage it to create the Model in the Model Editor, that means:

I created a Material with the texture, I manage it to import the Mesh in the Editor, then I picked the Material and it gets attached to the Model => The Model is visible and has it's texture.

But when I will set it in a Level, it hasn't it's material anymore and its unvisible... Has anyone an idea, what is wrong?