Difference surface / face

[rvdkruk]

Hi,
I'm running in to this texturing problem.
I'm trying to give an existing car model a good windowglass material.
In the picture you can see the backwindow has nice reflection but the side window stays grey/dull.
They both have the same material but entityinfo says one is a face and the other a surface.
Anyone familiair with this?

[nomeradona]

reverse the material or apply the material on both side.