Thus, unless DE knows a way to patch (I tried doing something like this using the technology for video game patching but it wasn't compatible with VOBs), the solution is to demux to elementary streams, replace the offending audio, and remux. And muxing alread-authored subtitle streams and menus is not just point-and-click.
The best solution is to get on the pyramid. That way somebody'll just mail you the fixed disc. For the few bucks you spend paying it foward, it becomes well worth the time.
If only Lucas took the same amount of pride in his product our green lightsabers and swapped music would have been fixed by him.