I managed to get use my email server rather than my web host for outgoing mail using a different port as you said.
I then spoke to one of their support staff about the type of email that it uses (qmail or sendmail)
Apparently it uses something called Exim instead. However, they said using sendmail should be fine, although procmail is not supported.
The support person thought this would still work, but since testing it by sending "TESTBOUCE" from another email address, I don't get an automated reply.
When I click "Test mail settings" from my configuration page, I do receive an email to my bounce account, but this doesnt mean the cgi. is working properly does it?
Also....will this cgi run with Exim?