Using m0n0wall-1.0 on a net4501.

Problems:
- In bridge mode with filtering off, it works like expected, but when I
enable filtering bridge most of the times I can't get traffic from OPT1 to
the outside (WAN) network. Incomming traffic works fine (WAN->OPT1).
(sometimes it works, stops working after a reboot)
- Also sometimes the LAN interface cannot be reached, after rebooting or
re-assigning the ip through the serial interface makes it work again.
- m0n0wall works fine in every configuration for me except in the filtered
bridge mode.

Config:
-Made a bridge from OPT1+WAN.
-Enabled filtering bridge
-LAN has still 192.168.1.1.
-Firewall rules, both OPT1 and WAN have PASS, protocol all, source any,
destination any.
-Enabled advanced outbound NAT (to prevent auto natting)

Questions:
- Any idea what the problem could be?
- Why does the WAN interface want an ip? what should I fill in?
- In the OPT1 network there is also some commnucation between de servers
with private network ip ranges, could this cause problems?
- Is there a difference between an OPT1-LAN or an OPT1-WAN bridge?

Thnx.