Outputting one material channel to another

Hi guys,

I'm approaching the end of an animation project, and I'm attempting to animate a material for a flow effect. The effect is a glowing liquid that relies on a series of bitmaps that drive the alpha and luminance channels, and layered gradients will control the local strength of each. The data in the alpha and luminance>colorizer shader needs to be the same at all times.

I thought that I would be able to use Xpresso to import the alpha's output to the colorizer shader in luminance, but for some reason Xpresso doesn't support inputing actual texture data to ANY material channels or shaders at all. It's the first use of Xpresso with materials that I would have thought should be allowed, but where this key feature should be, there is a giant hole in the software.

I have some experience with text-based scripting in other software, but I don't have time to learn the particulars of Coffee for this project. Is it possible to output the alpha to a colorizer shader with COFFEE? What would the code look like?

It only has to be good enough to make the luminance colorizer match the alpha of this material for the duration of the animation. I would think that it's a matter of just saying ~ Colorizertexture=alphatexture and whatever other stuff is needed to identify the material and initialize whatever needs initializing.

If anyone can help or point out what I need to do that would be awesome. Thanks.