Is the guy really a rock star? Seriously? Think about it for a second. Is he smart, but doesn't get things done, or is he both smart and able to get things done?
Think about it really hard.
If he really is a rock star, then maybe you shouldn't mess with him. He's producing incredibly awesome things using his own process. Just because there's a different way of doing things that works best for you, doesn't mean that's going to enable him to produce his best work. Instead of trying to get him to bend to your process, which very well could kill all of his awesomeness, you should try and find a way to accommodate the way he works.
If he really is as good as you say, you shouldn't mind doing that. If it isn't worth the effort to do that, then he really isn't that good. In that case, you don't have a rock star, you just have a mediocre programmer that doesn't like to play be the rules. Those guys, you should just get rid of. A temperamental rock star is usually worth the pain, though, because of the quality of what he or she can produce. Those people, you should go to great lengths to keep.
