Amazon payment gateways

I'd really, really like for the Amazon payment gateway to work in Membership plugin. It doesn't...only the free subscription and paypal express payment gateways show.

I'd also like an Amazon payment gateway for Pay to Blog as a choice in addition to the Paypal. My target market is into Amazon.

I tried to write one using the supporter amazon payment gateway to modify the paypal pay to blog gateway...but now how to call it?

Sheesh. It is beyond me. Please help!