I'm trying to recreate a scene in Carrara Studio 2 of an animation that I did in 3DSMAX 2.5. Essentially, all I want to do is pseudo-render some clouds by having a bunch of 2D plains with texture maps and an opacity map where the texture goes completely transparent in dark areas on the opacity map:
However, I have tried and tried and tried to get this to work in Carrara with little success. To recap, all I want is to texture a 2D plain with a corresponding opacity map. For some bizarre reason, if you use black on the colour texture it blends out properly to 100% transparent, but this is useless because it gives the clouds black edges.

As you can tell from the screenshot, it's not fading out to 100% transparency. :( Any advice at all would be great. :)