I was having a similar issue... LQ users helped me get it sorted:
http://www.linuxquestions.org/questi...server-752978/
Note: you have to turn the postfix filter on, as it is not on by default in debuntu. See confs in /etc/fail2bind
And yes, I suppose you could receive mail on 465 and relay on 25, or vice versa... but I don't think that's going to solve your problem.