"Well, let me tell you what I did for my SW DVD. I had two soundtracks - The first track was the PCM LD soundtrack, and the second was the AC3 commentaries.
I did not want to have to manually switch between the soundtracks when I went to the commentaries, so I set it up like this.
The first track is technically Track "0". Because my DVD intro was a Dolby Digital trailer, that meant that track 0 had to be AC3 for all movies, which meant that my commentaries would be Track 0 for the film, and the soundtrack would be Track "1" (the second track.)
To automatically force an audio switch, do this: Connection -> Add -> Add command object -> VTS domain
You will get a white box. In it, you will put one of these two commands:
SetSTN (audio=0 )
SetSTN (audio=1 )
When my DVD started, the Dolby Digital trailer would play with Track 0 (AC3). Between this movie and the root menu, I placed the "SetSTN (audio=1)" command in the "VTS domain" menu so that the player would switch
to the second track (PCM) for my film. Now, at the bottom of each chapter menu page, there would be a "Commentaries" button. If the user selected this button, it would go to another "VTS Domain" menu which said "SetSTN=0". While the user was in the commentaries menu, the first track (AC3 commentary) was automatically selected. It would stay this way until the user chose the "Return to Main Menu" button, which was again routed to a "VTS Domain" menu which stated "SetSTN (audio=1)", setting the player back to the PCM soundtrack for the regular chapter menus.
While this is a little harder to program (at least, the first time), it makes navigating the DVD tracks much easier. The track that is to be played is already determined depending on the menu you have selected."
Worked like a charm for me.