Probably the texture itself is rendered in 16 bit, so that the shadowmap is not the actual problem? AFAIK it can be found in the manual that textures from a .WAD file are always rendered in 16 bit colour depth. You could try and use WED's "Add folder" option instead of a .WAD and see if it does any good.
Formerly known as The Matrix - ICQ 170408644
I've been here for much longer than most people think. So where's my "Expert" status?