Send RSVP email only after successful payment for the event

With paid events RSVP (attendance) is set one a user clicks "I'm attending" regardless whether it's been paid or not. Only after that user is asked to "buy the tickets". If "Email: send email on RSVP" add-on is enabled, an e-mail is being sent to the user immediately even if no payment was made.

The RSVP status auto-reset add-on can remove attendance form event if a user doesn't pay within a defined amount of time but how to make RSVP emails to be sent only if an event had been paid for?