Ahhhh, I get your audio question now. IIRC, swapping channels in Vegas really just involves right-clicking on the audio and selecting swapping channels. You can also select one or the other channel to play. If you do this, you can also add a panning envelope (INSERT, from the top menu), and use keyframes to move a sound from one speaker to the next. If you are creating a 5.1 soundtrack, you can pan around all the speakers. I once created a cool soundtrack by inserting the Jaws "Da-da" sequence, and slowly turned the entire soundstage around the listener as it played. Awesome effect!

And vegas and Premiere will do the things you want to do - the problem is knowing how to do it. If you want to learn more about Vegas, I highly recommend this book: Vegas Workshop

I have the book for Version 5, and it has some awesome explanations and examples. I've learned a lot of neat tricks with it. As for Premiere, I use it solely for video stabilization and nothing else, so you'd have to ask someone else about that. I know Zion uses it.