Feature request:(Option to have) background with black alpha

[Woedend]

It would be really useful to have backgrounds that instead of producing a solid alpha have a black alpha. That way the unprmultiplied files we end up with would be much more usefull in a composite. And those who don't want the transparent background can simply ignore the alpha. A checkbox in the environment tab (or even per material) that toggles the alpha of the background system would ofcourse be even nicer.

[radiance]

Hey, alpha is planned with non or multiplied options for the next 2.3...

Radiance

[bazze]

there's a easy work around that you can use right now.

1) Set your materials to pitch black
2) Set the environment to 100% white.
3) Invert picture in PS.

voilà...