I believe the equivalent to Server NAT is 1:1 NAT in pfSense (sorry don't 100% remember, I haven't used m0n0wall for quite some time). To add IPs to your outside interface I would use CARP but that is my opinion as most of my configurations are for failover firewalls. I hope that answers your question.
-- Curtis LaMasters http://www.curtis-lamasters.com http://www.builtnetworks.com
