Up to 3.3.0.1 it was possible to set an NAT open port with a destination IP reached via a static local (LAN) route that was not viewable in the 'Choose PC' dialogue.

However despite the routing table functioning perfectly for traffic it now seems that you cannot do this, instead returning an 'Local Computer IP address is invalid' error. This means that it is no longer possible to set a WAN port to a routed local IP.

e.g.
Router IP 192.168.0.253/24
Static route 192.168.1.0/24 via 192.168.0.1

ping 192.168.1.10 - OK

NAT>Open Port 12345 to 192.168.1.10 (Error:Local Computer IP address is invalid)