No way to permanently change Uke's name unless you manipulate the game code in some way to change the hard coding of player 2's name.
A.k.a. find the file that codes for uke's name and change that.
You can only change the name via. /lp or changing the name on the 'BOUT 1;' in replays. Textures by changing the .tga files in customs.
happy hacking :^)