Cockpit and OpenLMI system management projects need systemd DBus API [1] to be authorized by polkit instead of plain DBus authorization. 1: http://www.freedesktop.org/wiki/Software/systemd/dbus/ See http://lists.freedesktop.org/archives/systemd-devel/2014-July/021262.html (and whole thread) for more detailed method list.
A patch has landed in systemd git master for polkit support, but it has not yet been released: http://cgit.freedesktop.org/systemd/systemd/commit/?id=283868e1dcd8ea7475850d9c6e7d4722c473dd50 In addition it does not enable interactive agent based re-reauthorization. systemd upstream would like to create a DBus flag for that, and is being discussed here: http://lists.freedesktop.org/archives/dbus/2014-September/thread.html
Fully implemented in git btw.
This is part of systemd 219 in F22+.