Need to set up mailserver in a vmware virtual machine

I've been using this ( http://mailserv.github.io/ ) mailserver for a while, but for various reasons, I need to set up the basic virtual machine again. I will do the actual administraion of the server, ie: set up domains, users and such.
You should be familiar with OpenBSD as this is the operationg system this mailserver is running on.

NOTE: Our requirements for mailserver is: mulitple domains and users, sercure connection via self signed sertificate, and optional webmail. And of course spam/anti virus control. We can consider other options based on your experience, but pererably open scource with no or minimal running costs.