Network address translation (NAT) is not supported for SiteScope monitors that require a remote host definition.SiteScope is unable to determine if an external (real IP) or internal IP (NAT) is used when you configure a monitor with an IP address or host.
But most of SiteScope's customer are Large scale company
they often need to monitor NAT environment.
Please consider enhancing SiteScope let all monitors can support NAT environment.
Thanks and Best Regards