Never mind, solved it. For those who are wondering, go to
System> Misc Clients > Add.
Also, note that dyndns.org no longer offers a free dynamic dns service, but D-Link does! Go to
http://www.dlinkddns.com/ to sign up.
NOTE, only 1 IP address can be hosted on this service. If you require more, you may need to purchase additional services from dyndns.org.