[otrs] Radius Authentication & Creation Customer Users db

Hi, I've activated in my OTRS Sytem a Radius Authentication for my Customer Users and It works. Can I create my Customer Users db getting information by my Radius Server or have I to create them before in my db? Is there a method to populate my cutomer users db dinamically when a customer user log on? I know that there's a system for Agents throughout LDAP but I didn't find nothing for Customer Users for Radius. Thankyou very much. Alessandro