You'll find it here:
For some reason, these properties don't show up in the pop up Properties window you get when you right mouse on the page and select Properties.
Hope that helps,
I think what you are looking for is this:
Make sure you chose the popup layout
Hope this helps!
Edit: It is the same as what Mike suggested, but with a different edit access. I right-clicked an empty space in the popup page and selected 'Properties'. If you don't see the handy view from Mike's post, you can enable it here: