Finding MAC Addresses on bridge interfaces

[Mark Mumby]

Hi,
I am running FreeBSD 4.9-RELEASE as a bridging ipfw firewall. What i
would like to know is how to get the mac addresses of the upsteam and
downstream neighbors (mac addresses of devices either side of the
bridge) showing what interface they "appear" on.
 
Using arp -a seems to associate the mac addresses with the interface
that is configured with the management ip address 
 
ie
                LAN A
                    |
         rl0 192.168.4.200
                    |
                 bridge
                    |
          xl0 un-numbered
                    |
                LAN B
 
When i do a arp -a, addresses on LAN B say they are on rl0 not xl0.
 
 
Thanks
 
Mark