To manage the accepted credit cards you click on Settings in the black bar at the top. Then click on Booking Engine under Business Configuration heading.
If your logged in, you can click here to take you there.
Enable Accepted Credit Cards in the Booking Engine by clicking on the ones you wish to accept.
Booking Engine Settings
Click Save at the bottom when you are ready to commit to your changes.
This feature will allow it to display in the Booking Engine during the online Reservation process. Allowing guests, the knowledge of which credit cards are accepted.