The port forwarding is done on the virtual server screen.
- Check Enable
- Enter a description, e.g. "BitTornado"
- Inbound port = 6881-6899
- Type = TCP
- Private IP address is the LAN IP of the computer that will run bittornado
- Private port = 6881-6899
Verify that bittornado uses the same ports you set in your router and note that you only need to forward as much ports as you want to run instances of bittornado at the same time.
You also need to apply your computer a static IP outside the DHCP IP address pool
http://web.belkin.com/support/kb/kb.asp?a=2824.