There should be no sync issues if you’ve created the audio files correctly.
If you really want more of a Hollywood approach to changing the audio, try this:
Create two more buttons on the Menu (Insert>Empty Button).
Name one Audio One (or whatever) and the other, Audio Two.
Set Audio One so that its Destination is the Manu Page that it’s on (specify the page by name).
Set Destination Button to be The Video.
Set the Audio Track to 1.
Do the sames for the Audio Two button except the audio track is set to 2.
Now, when you hit the audio button, the highlight will bounce back to The Video, but the audio playback will be reset.
Gary Kleiner
Learn Vegas and DVD Architect
http://www.VegasTrainingAndTools.com