1. Right now the plugin doesnt use the standard Gravity Forms Credit Card Field (like this: [url removed, login to view]) for user interface, you need to implement that. I will provide you with the Credit Card Field.
2. You need also to design an ready to use Field (pretty much same as Credit Card Field) for Payment Option Direct Debit, I will provide you with mockup (Field need to include input field for name, IBAN and BIC)
3. Right now the Payment Plugin itself comes with a drop down menu which you need to insert into the form where the user can select his preferred payment method (i.e. Credit Card or Direct Debit). As I got several other Payment Plugins developed for Gravity Forms I know that the best way of choosing payment method is to trigger the payment method based on value check of Radio button/Drop Down menus in the backend itself. That means that instead of using that Drop Down Menu you need to implement (same es Gravity Forms PayPal Plugin) a menu to set conditional logic in backend. I.e. trigger Credit Card payment if field"payment method"=creditcard or trigger Direct Debit field"payment method"=direcdebit. If you do it like this I can use the WireCard plugin with several other Payment plugin and define their use based on conditional logic.
All of the functions already exists, I will provide you with mockup, the plugin and other payment plugins which demonstrate the front-end/configuration styles I described.
I calculate that you need 2-3 hours for that. Easy and small project, please only apply if you are familiar with Gravity Forms. I will ignore all spammy applications.
Good evening, I can begin on the design and front end changes for the form later today, please let me know when you are available so we can discuss the timeframe and your budget. Kind regards, Villy