Creating shadow from Green Screened person mapped onto a plane

I have been able to map a person shot against green screen onto a plane in Invigorator Pro so the figure appears very realistically in the 3D scene. However, when I set up the lights so they cast shadows, the plane that the person is mapped onto is what casts the shadow--a big rectangle. Is there a way to set it up so the shadow of the person mapped is what you see? Or is the only way to have a person mapped onto a plane is to do it without allowing any shadows? Thanks, Bob