I just saw this on xbox.com DoA3 forum, don't know if there is any truth in this!
Subject: Nude Kasumi
From: "Mai" <MaiSNK@hotmail.com> Sent: 3/21/2002 1:51:44 PM
Bet survival with Kasumi. You have to bet 1000 cpu
players once you do that select Kasumi hold down L1 R1
push down on the left analog stick and press Y & X at the
same time. It really works.