If you wish to control all DNS services on another server and do not need to run named (bind) on your DirectAdmin server, you can disable it by doing the following.
1) edit /usr/local/directadmin/data/admin/services.status set named=OFF
2) Stop named: RedHat:
/sbin/service named stop chkconfig named off
FreeBSD:
/usr/local/etc/rc.d/named stop
3) Edit /etc/init.d/named (FreeBSD: /usr/local/etc/rc.d/named) and set the file to show:
#!/bin/sh exit 0;
This will let DirectAdmin think that it's reloading named, while the script will actually do nothing.
With these changes the dns settings will still be made, but no program will be running to host them so they will have no effect.