Finally, I recommend you read this post. It helped me understand how to set up the 5.1 surround in Premiere Pro better. A lot of things to line up, huh?
Want to learn how to do Dolby 5.1 without paying for Surcode?
http://forums.adobe.com/thread/921599
Key points as I understand them:
1. Your "Master" audio has to be set to 5.1
(You can't change a sequence after the fact, so create a new Sequence and under the "Tracks" tab, make sure the master is 5.1)
2. Your source tracks can be stereo, but once you assign the output of that track to the 5.1 Master Mix (or a Submx that is 5.1), you can use the puck control to position the audio within the sound space of the 5.1 (L Front, R Front, L Rear, R Rear, Center, Sub).
As I read, I am recognizing I may have some research to do and challenges ensuring the exported file or created DVD plays the 5.1 surround sound. I guess I will cross that bridge when I get to it {sigh}. But, I am doing it with a very short test project ... not trying to tackle the learning of this within my 1 hr 50 min movie.
Again ... I hope that helps!