3ds Max :: Creating Etched Glass Pattern On Existing Glass Window

Any way to put a detailed patten into my glass window.

I have created glass with the slate material editor, used specular 100, glossiness 80 in the Blinn dropdown. Ued mental ray. Looks good, very glassy. Now I want to put a pattern on the glass, like a silouette, only that it is also translucent, part of the glass, as though it was an "etched glass" pattern on the glass. Do i make the pattern into some kind of "mask"? and lay it over existing glass?