I ran doc.tikiwiki.org for its first 6 months of existance behind my NAT firewall here. All I did was open port 80 to a server and in admin->General give it the doc.tikiwiki.org name. All internal machines needed to have there hosts. file modified to that :
and then when an internal network machine ping's it went on the internal addy
You can see here http://doc.tikiwiki.org/tiki-pagehistory.php?page=HomePage My 192.168.10.xxx addresses.