Problem with Overnet?

Well the problem is simple... I run the newest version where the temp files are divided into many, like "1.1.part, 1.2.part" etc. my problem is I have a download that won't finish and I remember the old temp files where you could just rename the extension and have the file anyways... how do I do that with the new ones? The file I'm downloading is an avi file and is only missing one lousy kb! It simply won't finish no matter how long I let it be, so help on this is greatly appreciated!