Membership Upgrade (for existing members, including free members)
After the payment is complete, click on the “I have an existing account” radio option displayed above the registration form, and log in again into your account. If your Paypal e-mail address matches your account e-mail, the log in screen will show up automatically.
Note: The same actions – register a new account or log in – should be taken after the payment is complete regardless on the membership or the renewal type (manual with the buy now buttons / automatic with the subscribe buttons).