There is a new feature which allows you to add a new card directly into Windcave, creating a re-billing token, without having to first make a payment or authorisation. This can be done by selecting the "Add Card" button indicated below.
This will open the same window through which you usually add cards to Windcave when making a new payment. You simple need to enter the credit card details, submit them, the press "Next" until you get to this page. If you close the window before this page appears, the card will not save.