This is likely an uncommon issue, but for those who have run into issues with inability to get NAT type 2 through a PFSense router, as long as you have UPnP enabled, the problem lies entirely in your outbound NAT rules. You don't need -any- manual port forwarding rules. UPnP will handle that for you.
The solution for this can be found here:
http://doc.pfsense.org/index.php/Static_Port
Simply put, PFSense randomizes your outgoing ports to prevent spoofing. The Sony servers don't like this with the Vita. The PS3 deals with it fine though, which is something I don't fully understand. Ah well, hope this helps someone!