Are you using a login manager at all? Some of these options might not be present if there's no display manager active, such as kdm or gdm. You seem to be login in from command line, is that true?
Modern gnome versions that use consolekit to manage this stuff can be run this way, which will give you the ability to manage sessions even if there's no display manager.
exec ck-launch-session gnome-session
This also grants privileges to processes needing them such as nautilus (to mount drives and that stuff). But I have no idea if kde 4.x has this capability. If not, just use kdm to login.