You do not need to configure anything on the gateway side. You are correct about the useage for each of those tabs, but the gateways are only if you want to override what normal routing would normally determine. Bindings are where the service 'listens' for connections.
Buttercup's Route Table wrote:Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 192.168.0.60 192.168.0.67 20
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
192.168.0.0 255.255.255.0 192.168.0.67 192.168.0.67 20
192.168.0.67 255.255.255.255 127.0.0.1 127.0.0.1 20
192.168.0.255 255.255.255.255 192.168.0.67 192.168.0.67 20
224.0.0.0 240.0.0.0 192.168.0.67 192.168.0.67 20
255.255.255.255 255.255.255.255 192.168.0.67 192.168.0.67 1
Default Gateway: 192.168.0.60
A route table will look something like that. Now, normally, the mainframe system will be, for example, 192.168.0.5. That is on the same subnet reachable by normal routing, so you shouldn't need to configure anything for it.
Gateways are normally only for people who have multiple interfaces and want to ensure that traffic goes out a specific interface (Such as ADSL + Dial-up, with telnet over dialup and HTTP over ADSL, etc.)