$USER_DATA['username'] definition.

[DenVault]

Hello!
I have a problem with finding where the $USER_DATA['username'] variable is first defined. The reason I need it is in following:
I need manually change charset for every username loaded from the MySQL. I tried to find it almost everywhere (the most likely variant is still udb_base.inc.php$)) but when I see a variable definition and try to redefine it right after that -- I get no effect, USERS in admin page show me the same picture and the same stuff with private albums.
I need to find a place where I can redefine $USER_DATA['username'] in such a way every user can see theese changes.
Thanks a lot!
Best regards.

[Stramm]

yup, udb_base.inc.php
define('USER_NAME', addslashes($USER_DATA['user_name']));