There must be a way to do this, most clothes are much the same anyway. I know someone made a v2 to v3 clothes converter thing that was free but I dont know about stephanie to v3 if someone hasnt done it yet, it would be nice if they did (hint hint) If it is stephanie 3 petite you meant then that should be fairly easy to do as v3 and stephanie petite were both made with the unimesh, though the bones may be done slightly differently.