Hi, I have registered with IPTEL online proxy with registered users. But when I try to make a call using the alias phone number of the user(INVITE will go with phone number(aliasnumber(a)iptel.org) but proxy is not rewriting the To field in INVITE message that is sent to gateway.Is there standard message format for the REGISTER message to get the rewriting of the URI.Thanks for your response in advance. Regards Sudhi