My girlfriend currently has a slightly unorthodox set-up on her road bike with a Dura Ace 7401 7-speed rear derailleur and newer Shimano 7-speed "V-brake" integrated brakes/shifters, you know the ones I'm talking about. Indexing is fine and dandy. Anyway, she wants to switch to STI levers, so my question is: Will only DA 7-speed STIs work, or could something else?