[Freeswitch-dev] Connecting Two Freeswitch Boxes and Presence

Dear All, I have successfully connected two Freeswitch boxes together using IP authentication (as described on the wiki page http://wiki.freeswitch.org/wiki/Connect_Two_FreeSWITCH_Boxes). Calls are working as expected. But I would also like publish/subscribe to work across the two boxes so that clients registered on BoxB can subscribe to the presence of devices that are registered on BoxA. Is this possible? And if yes, could anybody tell me what changes I need to make to the config to enable this behaviour? Any help would be appreciated. Thanks, Anthony