Ok i faced a major problem. My previous video was made with a rabbit who cast shadow on mine Video shots..
I just used " Usebackground" material and everything works out.

But now with my scene setup the usebackground is not working ... Any ideas how to make those shadows cast on mine jacket and not to render the plane... I've tried a lot of settings but nothing seem to work ;/

Here are some screens with the scene and what i want.