After spending thousands of hours (literally) designing in IV with Vault I can say that the IV browser should be seperate from the Vault browser. I say this because having to switch back and forth DOZENS of times a day is not the way to go. If the two browsers were in seperate windows I coulsd easily see the info. I need and make my decisions in a smoother way.
Also, I would suggest some sort of cross association between the two. If I slect something inthe Vault browser I want to see all instances of that file highlught in the IV browser and vis versa.