[Users] Customize messages [max_contacts]

Hi gyus, I configure my openser to restrict the number of register with the same user using the function [max_contacts], and functioned perfectly. # Allow no more than 1 contacts per AOR modparam("registrar", "max_contacts", 1) Whenever that a user tries to register using the user that already register, the system return the following message: "Registration error:503 - Service Unavailable" I need to customize the message informing the user the reason of error, something as "user already registered" (softphone). I effected some tests, but I did not have success. Something as: if( t_check_status("503")) { t_reply("503","User already registered!!!"); exit; } Any sugestion ? Regards