That's a fairly complex setup with two NAT devices in a row. I was going to give you the link to the specific instructions for each model, but since there's several versions of BEFW11S4, I'll give you the entire list instead: http://www.portforward.com/routers.htm You should be aiming at using Port 6346

Within LW you'll also need to Force ip which will be the easier part: Force IP instructions & sample image