First things to check would be Bridge settings - make sure Enable Publish Information and Receive Information options are enabled in the presence tabs.
You will need to choose users / groups that presence will be published across the bridge for and which users / groups will be able to see this. This needs to be done on both sides of the bridge.
Finally, check firewall ports and fqdn / ports are correctly specified. If that doesn't do it try and substitute the ip address for the fqdn.