Every time I use a circle collision mask, friction is completely ignored. I tried reducing bounciness to 0 (and friction to 100, even when I suppose anything above 1 will be 1) in both objects, but the ball completely ignores the friction.
I would do a polygon collision mask, but I want a very big circle interacting, and that just wouldn't work.
http://dl.dropbox.com/u/41192999/friction0.capx <- capx demonstrating.
PS: I don't know if I'm doing something wrong, otherwise I suppose it's a bug (because a ball should stop down a hill if both have such friction!)