The way to do it is to go to the nova lobby through your favourite browser.
http://208.231.90.233/df3out.dll?suc...=df3out_r8.htm for DFLW v.37
http://208.231.90.234/enterlob.dll?S...=tfdlogin1.htm for TFD v.07
Then login with your usual user name and pass and go to MyPlayerOtions and change the name. You can either copy and paste or use Alt+000 technique.