Video Texture with feathered alpha

I was wondering if there is a way to make a video texture with a feathered alpha, that is where I could have the edges of the video fade to complete transparency when applied to a surface. I am basically trying to get the effect of a floating ghostly head projected onto a flat object. Currently I am using a material with a wmv video file plugged in with a feathered alpha mask plugged into the opacity mask. It masks off ok but the masked off edge is a solid line rather than the fade that is in the opacity mask video file.

Is this possible or is there another way of achieving a ghostly head effect, like projecting the face video onto a particle cloud or something?

Thanks in advance