Instructions in here appear to be outdated/wrong...

There's no entry called 'gnome-wm' in the start up applications menu.

So, how do i disable metacity and replace it with xmonad instead.

Just so i can backup my configurations. Where are the start up apps configurations saved. I guess the answer would be something like 'in gconf'. So, to be clear: which file must i backup if i want to mess around with the start up apps in a way that my DE gets unusable?