What I suggested earlier does work if you have the material editor and work on the materials in the head. There is a transparency factor that you set to one. This doesn't take it out entirely. The flesh tones show up. To overcome this, you have to create a new node on the diffuse color and insert a 2d image map which matches the background image. Choose a color in the color swatch that matches the background color most closely. You have to do this for skin head and skin scalp. The lips appear as disembodied and don't blend with the wall though. You can set the parameters for the eyes to be visible which makes it kind of bizarre.