I want to add a decal to an assembly that consists of three parts mated to each other.  I want to have the decal run across the three parts on three coplanar surfaces.  It looks like I should be able to do this by selecting Label in the mapping dropdown, but there is no label option there.  I also note that the four icons in the Selected Geometry dialogue are grayed out.  Why can't I select Label?

SW 2011 SP5.0