In the man rt-mailgate I found that:
Much of the set up of the mail gateway depends on your MTA and
mail routing configuration. However, you will need first of all to
create an RT user for the mail gateway and assign it a
password; this helps to ensure that mail coming into the web
server did originate from the gateway.
So, where should I “say” rt-mailgate which user/password I created on RT
through the web interface?
PoP-SP/RNP - Ponto de Presenï¿½a da RNP em Sï¿½o Paulo
CCE/USP - Centro de Computaï¿½ï¿½o Eletrï¿½nica da Universidade de Sï¿½o Paulo
Tel. (11) 3091-8901