Is it possible to use a Shimano rapid rise derailleur (m-970) with a set of rapidfire shifters? The Shimano website says that the m-970 derailleur is "best matched" with dual control and that the m-971 rear derailleur (top normal) is "best matched" with rapidfire. On the other hand, Shimano's site also says that their xtr rapidfire's are compatible with all 9-speed derailleurs. I like the idea of rapid rise now that the new XTR shifters can shift multiple gears in either direction.