I'm looking for a way to use BitBlt (and eventually StretchBlt) with a 256 color greyscale mask. I'd like to composite two images together like so:

Layer2 = Image (With semi-transparency, derived from mask)
Layer1 = Background

I figured, just set the picture to whatever background, and BitBlt layer2 on top of layer1. I have a greyscale image i'd like to use to describe different amounts of transparency for each pixel.

btw, I've heard that this is easy to do in Win2k. Unfortunately, my end user target is not win2k or win me.