BGE: Use separate texture as alpha channel I want to use a separate texture (grayscale) on a material in the Blender game engine as alpha channel of that material, because I reuse the other (rgb) texture on another, opaque material.

I set up everything as depicted in the screenshots. The preview of the material looks as expected, but in the 3D view or in game mode (p), the material is opaque.




How do I setup this correctly to actually see the alpha effect?
Here is the test scene: http://www.file-upload.net/download-11505718/AlphaTestScene.blend.html

Edit: When I bake the alpha channel into the rgb-texture and check color and alpha in the influence, then it works. But it would be nice to have separate textures for each purpose (like specularity or bump maps).
I have pretty much the same as you have. 

In-Game



Alpha = texture that feeds alpha channel 
Color = texture that feeds color channel


Alpha color is not visible at all.
Where Alpha is transparent, nothing is visible
Where Color is transparent you see the material color
Where Color is opaque you see Color texture (rgb)


Material

 

Textures