I somehow had them working before in 11.10 but I don't really remember what did I do back then other than activating "load Gnome components on start up" in the XFCE's settings manager.

I've tried the same in 12.04 but doesn't seem to do anything, I specifically ask for the Volume notifications as other notifications used notify-osd or xfce4-notifyd but the volume one was Gnome's (I found that later) As far as I know it uses notification-daemonbut installing it instead of the other two doesn't give me the correct notifications.

I'm using XFCE 4.10

This is what I get from running gnome-settings-daemon in the Terminal.

(gnome-settings-daemon:3841): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1137:14: Not using units is deprecated. Assuming 'px'.



** (gnome-settings-daemon:3841): WARNING **: You can only run one xsettings manager at a time; exiting



** (gnome-settings-daemon:3841): WARNING **: Unable to start xsettings manager: Could not initialize xsettings manager.



** (process:3849): WARNING **: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files



** (gnome-settings-daemon:3841): WARNING **: Unable to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files



** (gnome-settings-daemon:3841): WARNING **: Name taken or bus went away - shutting down