Possible presence bug


I’m having troubles seeing a user’s presence on a legacy IM service. I’m logging on AIM using the normal AIM client and registering another user through the Openfire IM gateway. When I send a subscription request to the user on the AIM client, I get a subscription to that user just fine. But the only presence I get back from them is “unavailable.” I checked the AIM client and nothing in the settings blocks users. Also, the AIM user can see the Jabber client user just fine, and they can exchange messages perfectly well. Any ideas?