Created attachment 5443 enables systemd hibernation support for panel action buttons Hibernation through the panel action buttons does not seem work. I have investigated this and it seems that hibernation support via systemd is not implemented yet in xfce4-sessions. In the attachment you can find a patch which enables this. It is basically a copy of the systemd functionality already in use for shutdown and restart. I am currently using this on my Gentoo system patching xfce4-session-4.10.1. But it also works fine when used to patch the latest xfce4-sessions git version (commit 0d53dda3cfdd0827d071238ee3581c63790537a1). Suspend support seems to be exactly the same issue. I will probably fix it shortly in another patch.
http://git.xfce.org/xfce/xfce4-session/commit/?id=0bc5eb603a3ab4af930fac70e03cfe7aa63a399e Should also handle runtime detection of systemd and it should be fixed in git master now. Marking this as resolved. Feel free to reopen (or open a new report) if you find any other issues with xfsm.