Login credentials fields for payment processors

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I am creating a web app. i am using dotnetcharge control for payment processing. There are lots of payment processors supported,

 

I need login credentials fields for each processor.

 

Like for paypal transaction we need API Username, API Password & API Signature.

 

I want help finding these required fields for other payment processors like amazon, google checkout etc.

 

If anyone have done this pls share info.

 

Thanks in advance.