VPN would be simplest to use (once it's set up).  Setting up VPN is another whole thread and depends on your network gear, but once you are connected just make sure you know the static IP address of your XP-8.  I've had trouble where ID didn't see the XP-8 (in the list where you select Use USB/Use MAC address/Use specific IP address).  But, I could send the program without a problem by using the specific IP address of the unit.