Question:

I'm hosting mydomain.com with you. I want a subdomain (sub.mydomain.com) to be set up and pointed towards an external IP address. Can I do this?

Answer:

Yes, as long as the domain is using the FutureQuest name servers, you can set up an A record (or CNAME record) using the DNS Manager in your CNC for mydomain.com:
http://www.FutureQuest.net/GoToCNC/

If you are managing your DNS externally, you'll need to do this with your DNS provider instead.