Comment 6 for bug 357346

P.S. Of course, /usr/bin/xfce4-session could also do the necessary work (as an alternative to doing it in the scripts I suggested). And, now that I look at the source code, I see that the upstream xfce4-session does exactly that. Sigh... it looks like this patch removed the call to gnome_keyring_daemon_startup(), effectively disabling the correct behavior:

xubuntu_gnome-keyring-daemon-compat.patch

That patch ought to be reverted. Instead of fixing the original problem, it lobotomized xfce4-session.