[otrs] Customer web interface

Hello again, ;-) I'd like to be able to have different pages for creating the account and asking for the lost password. I've found a web page that uses links to the option create an account and recovering lost password using links like "http://domain/otrs/customer.pl?Action=CustomerLostPassword&SessionID=" and when you click on it they get a *different* form asking for the username, and the same for creating an account. I know this must be an stupid newbie programming question, but how could I get that?, what's what I'm not understanding? Thank you very much in advance, J