Can you be a bit more specific?  An example of a character morph and a clothing item that would not work even with the morphs copied over would be a good place to start so we can figure out what's going wrong.  

As for fitting clothes from V4 to La Femme there are several ways.  One of the quickest and easiest is Crossdresser.  You need to download it from the creator's site and buy only the La Femme plugin  from here.