Have you ever tried Real Band to make 6/8 out of any style? Double click the time signature box and you can change to many different time signatures. I got a 7/4 song sent to me and we both tried several different styles, mine were from 4/4 styles and they all worked. Here is a link to the thread.
http://www.pgmusic.com/forums/showflat.php?Cat=0&Number=376888&an=0&page=0#Post376888