View alpha maps in viewport.

Ok, so Im trying to view alpha maps in the viewport; I can get a mesh to render with an alpha map fine, and I can make a whole object show up transparent or semi-transparent in the viewport, but I cannot make the picture affect the transparency in the viewport, which is really bugging me. Does anyone kno how I can do that?

EDIT: actually, I found a way; before I had been trying to use pictures that were just black and white, and using “calc alpha”. But now that I am using pictures that actually have an alpha channell, clicking “alpha” in F9 whilst in Uv mode, it uses the alpha channell in the viewport.


i also wanna know… in 2.49 and in 2.5x

thanx !