First of all, you don’t NAT a URL, you NAT an IP address.
Whatever FQDN you assign to the remote server endpoint will resolve to an IP that will be NATted to the correct IP on the other end if you’ve configured everything correctly.
R77.20 is the software version, but it is very much End of Support on a 2200.
The 2200 itself is also nearly End of Support.
However, it should be possible to configure this.
If you’re mew with Check Point, it might be worth going through our Check Point for Beginners series on Network Security.
Even though it is on more current releases, the NAT configuration is more or less the same.