Is there anything that will remux an audio track into a set of vobs.

IE:

I have a authored dvd-r ready set of vobs but the audio is DD 2.0 becuase my authoring program doesnt support DD 5.1 and I want to replace the 2.0 track with the 5.1 track. Ifoedit will remux video, but I need something like that to do the audio.

So is there anyway of doing this, without getting another authoring program?