Both AOTC and ROTS used some of TPM's music, so maybe it is possible to reconstruct it. Furthermore I've got a rip from the AOTC-soundtrack taken from the rear channels of the DVD. It is called "Ultimate Edition", but of course it's not official and contains SFX in some parts. But maybe it's good enough to fill in the missing bits.
I assume that setting a DVD player to 2 channels on a 5.1 audio mix DVD will play the rear audio channels...I noticed that alot of 5.1 mixes place the soundtrack in the rear mixed in with a few FX, and dialogue echo...I haven't tried DVD Decrypter in IFO mode, but i'm guessing it will have the same or similar result.