I don't think they will do a name change at all. The best you can do is to make a new account matching your folding name and ask a admin to delete the old one (ask before doing this obviously to avoid being tagged for a double account, which isn't permitted).
MajorDomo has done this for me in the past and was able to retain all of my old stats/posts under my new name. I don't remember all the steps but it involved something along the lines of what Xilikon mentioned. Sending a well written, polite, PM to MajorDomo, or even better, an email to admin, would be the best place to start.