You can change your account name by this way:
- Open MyAccount.txt
- press Ctrl+a 
- then Suppr or Del 
- then add 0000000000: to the file.
- save MyAccount.txt
- start your PSP then put the account name you want.
Make sure it exists or if you don't have one create one on kow psp web site.

warcraftpsp@hotmail.fr