Changing FQDNS Name for CEM Agents only

Have a CEM only environemnt where machines are connecting to public IP only, these machine do not connect to coorporate network at all. I need to change the external gateway name from the public IP to a pubic FQDNS name. I found several registry key hacks and made it work, but wondering if Symantec has a better suggestion to make this happen. I want the CEM Agent to connect to the public DNS name of the Internet Gateway. 

thanks in advanced.