How do I add a payment option? pm_sofortueberweisung.php

How do I add a payment option? pm_sofortueberweisung.php

I want to be able to add Sofortueberweisung (pm_sofortueberweisung.php) as a payment option since I can use it for Authorize.net. How do I configure it and/or enable it to be used under payments?

Thanks in advance,
Scott