Exactly.

The only way I can see this being done is by isolating the dialogue (fairly simple, as it's generally the center channel of any 5.1 sound mix), then recreating the sound mix as well as the person doing so can. Unfortunately, this would require access to a lot of sound effects, and not just Star Wars sound effects - simple things like footsteps, clothing rustles, presence (that is, ambient sound), etc. Not to mention it would need to be mixed properly, and would probably never sound quite "right."

I wish you luck on this endeavor, but I have my doubts about the feasability of the project.