I don't think there is a way to easily edit the downloads.dat file (someone got an answer about such a trick on the Phex forum a while back http://www.gnutellaforums.com/showth...7619#post87619 ), but you should be able to see if the files are indeed identical by looking at their sha-1 hash. right-clicking the incomplete file in the Library Pane should bring up the otions to do a bitzi lookup or to get the magnet details and show the hash. The hash apparently ignores file names, but does recognize a difference of a single bit within a file.

I don't know the linux version, but I'd guess the options to check the hash are there too.