I am not sure if this answers your question, but I found this a while ago and found it to be most useful for enabling the FTP on the 320, but you may need to go over everything 3 or 4 times.  "http://www.youtube.com/watch?v=BCxdGWmrcOM&feature=related"  is the link. If the link is bad, go to YouTube and search FTP on a NAS.  I really wish they had "stickies" in these forums for common problems, known issues and work arounds, supported drives, and assorted guides / links.  Actually, I am kind of amazed that they don't, it would really make their equipment much more user friendly.  Anyway, good luck.