I've always kalk-pasted them. It helps to either make an uber-thick solution of it or to take the rock out of the water to do it (and not put it back in until it solidifies).
Might want to check out Sodium Hydroxide (I think.) I covered it in the first Reef Brief issue. It's nasty stuff, so research it first and be careful with it. I'd help more...but I'm kinda busy.