Is it possible to invoice a customer and have them pay at another time?

I tried to create an order manually, then assign the user as the Owner of the Order. However, when I go to the Payment tab to pay, only Example Payment shows up, even though I have the PayPal module installed and working at checkout.

I don't really need the customer to go to checkout, if they can just pay from the Payment tab, that would be great... but it is also okay if they go to checkout.

Any ideas? Or perhaps I am going at this the wrong way completely? Only users on the site can make payments, so we don't have to worry about anon users.