Let him suffer and change all the data every time. Until he starts playing fairly, but don't give him any slack, or other participants will be tempted to do the same.
P.S. Regarding this particular subject, I think he'll either change his nickname (which I suggested to him) and play fairly, or he's a complete idiot :D. You just need to see his moves.
I often regret that I don't have your ICQ.
True, I'm rarely online there. But if something comes up, feel free to contact me ;)