DNS problem internal/external domain

We have an internal domain name eastbalt.com and we also have the Internet domain eastbalt.com. Our network is Windows 2000 AD domain using DNS. Our web site is hosted by XO and the name to access it is www.eastbalt.xohost.com. I have been able to setup a forwarder for internet DNS so that if someone puts in www.eastbalt.com it goes to our web site. The problem is from our intranet www.eastbalt.com doesn’t resolve. XO told me to put in a cname record so that www.eastbalt.com would go www.eastbalt.xohost.com but this failed to work. They told me that they can’t give me an IP address to set up an A record with because of the way they do load balancing. Windows 2000 doesn’t seem to be able to do a web forward in its DNS. Is there another way to do this?