[otrs] Unique key

Hi! When I installed OTRS I thought that it was a really good idea t use the login as the unique field on the customer. I see now that it wasn't.. But can I *just* change this? Which tables will I need to update? I know I have to change config.pm so that CustomerKey points to my new and hopefully better unique field, but the relations will go bad if I don't update. :-) -- Camilla Krag Jensen