just to confirm... you have 2 NICs. one for the wug and one for the internet.
setup the wug NIC with a fixed IP, make sure you can ping your router(RB).
open an administrative command prompt and type:
route add 172.16.0.0 mask 255.240.0.0 [your RB IP here] -p
This is on a windows pc ofcourse.
thats all. job done