Same problem with default language (and country), when creating CP user and Client.
All default values set to RU, (in client.tform.php and users.tform.php), but not affected to combo box in panel. 'fi' language stay default. With Country (in Client) same problem. In client.tform.php default country set to DE but in panel, when create Client - default country - Afghanistan (first in select?)
ISPConfig 18.104.22.168 rc2, Debian Lenny.