1 object, 3 materials - 1 solid, 1 alpha no spec or diffuse, 1 alpha spec & diffuse

Hi folks, I’m having problems with the materials on a motorcycle fairing. I want to apply 3 different materials, 2 of which have alpha values. Basically I want to cut out holes for the headlights (all alpha no spec, no diffuse) and the screen (variable alpha, variable spec, variable diffuse) but I can’t figure out how to do it The first attached image shows the full shape of the fairing. The second shows a basic alpha mask uv mapped to it. The four little holes are for the healights and need to be totally clear with no spec or diffuse (I already have headlight lenses). The V shaped cutout above the headlight holes is the screen and this needs to have diffuse and spec so that you can see that it is perspex. My problem seems to be that when it comes to alpha and spec then Blender is either on or off across the whole object. Can anyone help? Thanks Sam


SCREEN.blend (1.95 MB)

I have done like this: create base material apply to all, copy of that with a z-transparency, and transparent plastic.
Select faces where lights will be, UV unwrap that part on a new image, bake alpha. Bring that to Gimp, make holes and apply to z-transp material. This material in turn is applied to what was selected faces.
Select faces for transparent plastic and apply where needed. If you haven’t done modeling so that edges are where transparent part’s border is, i would suggest making 2 parts actually.