Please click on the Add Method button under billing methods. You should be able to view this option:
Please let us know if you need further help. Thanks!
I have the same issue, I can add Paypal as a billing method but within the Paypal authorization window I can only select a credit card in Paypal, not my Paypal balance. I want to use my Paypal balance to paym NOT a credit card via Paypal. How can I do that?