The Windows Live Messenger support in GNOME 3.4/gnome-online-accounts as shipped in Fedora 17 is currently broken because of a server change. The 0.16.1 release of telepathy-gabble has the missing functionality. See http://blogs.gnome.org/xclaesse/2012/06/20/problems-with-windows-lives-xmpp-server/
Yes, I'm well aware of this. In the future could you please wait at least 24 hours before opening a bug like this, since it justs add to the duplicate bugs and e-mails I get on the subject. Thanks! *** This bug has been marked as a duplicate of bug 814210 ***