Bridge causes freezes

[Giulio Ferro]

I'm setting up an openvpn demon in bridge mode on a firewall.

Scenario:
freebsd 8 amd64 stable (last week), pf, vlans, openvpn in tun mode 
(different
port, of course), many routes

I've created the bridge interface in rc.conf like this:
cloned_interfaces="vlan.. .. .. bridge0"
...
ifconfig_bridge0="addm vlan35 up"


Everything seems to work as expected as far as networking is concerned.

The problem arises after an hour or so: the system simply freezes, and 
no relevant
log can be found after restart.

This _always_ happens, even when I don't start the openvpn bridge demon...

Any idea, anybody?

Thanks.