The syllable "jane" must mean precious (and about five other things) in Mandarin. Jane-Way becomes precious Wei (although why they didn't translate Wei I'm not sure).
17 explained to me how Revenge of the Sith became Backstroke of the West. Backstroke is a pseuo-archaic term for "hitting the other guy after he hits you", so I supposed that's sort of like revenge. Sith, obviously, isn't a real word, so they just tried to find a character that sounded like it. Apparently they couldn't find one with a -th on the end, so they went with Si- (Xi), which means West.