help for mirror map - window texture

I have this situation: I have made a town. The buildings that are situated at the depht of the scene are very simple. Let`s say they are boxes. I want to make a material that makes them look very realistic,although they are not infront of the scene -  they must have windows! So, i created Blend material. The first part is the wall material - the stucco. The second part are the windows - glass material. The mask is black rectangles on white background - i made it in Photoshop. Very simple mask. The idea is that the windows won`t be 3d objects - they will be mirror map - placed on the black /or white - doesn`t matter/  rectangles of the mask. The problem is that i can`t make such a good material - for the windows. It must be raytraced material, or something. It must reflect the other buildings, the sun, the sky, etc. I don`t know what`s the best solution for that. Can you help me in this task? It`s very important to make the buildings look realistic.

you don't need a map for raytrace. . .just play with the IOR (index of refraction) settings and transparency untill you like it. . .also make sure that the material has reflections set on if you want those, too and do experiment with them as much as possible.  It took me a good week of work to discover all the subtle uses of raytrace.