Just a suggestion since I haven't tried it, but have you considered
connecting the TCP/IP output from your computer to a hub, and then
connecting one port from the hub to the we800g to feed the ethernet
LAN, and another port of the hub to the Linksys router handing WAN
protocols? I've lost my copy of "Internetworking Using TCP/IP" but if I
recall correctly, LAN and WAN protocols are not directly compatible.
Perhaps all you need is a simple network hub to solve the problem,
since the we800g may be sifting out some of the data needed for
bidirectional WAN Internet connections.

For what it's worth I'm currently cable connected to a Linksys WRT54G
wireless router (driving 4 additional computers via wireless
links...wife, daughter, son, etc.) that is connected to a Linksys cable
modem for Comcast Internet access. My LJ4+ B/W printer is on a wireless
link from the router, as is a color printer on my daughters system plus
a flat-bed plotter located in another area of our home. I haven't owned
any strictly ethernet equipment in nearly 8 years.

Hope this helps. Harry C.