On the internal DNS create a new A record and name it ts.nortec.com and point it to the internal IP address of the TS.
Then contact your ISP and ask them to create an external DNS entry (assuming you are not the one managing the external DNS entries) for ts.nortec.com that points to your external IP address.
Finally configure your firewall to allow port TCP 3389 to go to the internal IP of your TS. This is usually called port mapping.
Cláudio Rodrigues
Citrix CTP