I just did another hostname change, this time I started from within DA (Admin Level -> Admin Settings -> Server's Hostname).Way back when I wrote it, that's just how I designed it.
Reason was, to keep it separate for more control (although I've never seen a case where it needs to be separate).
Current guide to change hostname:
http://help.directadmin.com/item.php?id=405
John
[oldserver's hostname]'s DA is down...