configuring if_bridge with stp at boot in /etc/rc.conf

[Nik Lam]

I've tried rebuilding a kernel with

OPTIONS if_bridge

but this problem still happens.  To re-iterate, when I try to activate 
the bridge with STP parameters in rc.conf, one of the bridge interfaces 
goes into forwarding mode, but the other interfaces remains in disabled 
mode.
Here is what I have in rc.conf:

#===============
ifconfig_em1="up"
ifconfig_em2="up"

cloned_interfaces="bridge0"

ifconfig_bridge0="addm em1 stp em1 addm em2 stp em2 hellotime 2 maxage 5 
fwddelay 6  priority 10 up"
#===============

If I remove these lines and reboot, I can get the STP bridge to work if 
I just use ifconfig to manually build the bridge.

Is this a bug or have I missed some documentation somewhere?

Nik