Add-on payment module needed for osCommerce using Payment21 gateway

Create Add-On Payment Module for Payment21 on osCommerce online store solution. Please create an Add-on of our payment method on osCommerce using our simple API making it available for quick integration with Payment21®'s payment method: Instant eCheck?"?. Please use our API for - integration into a one-page checkout into osCommerce - Merchants should be able to configure what payments methods are available? - Merchants should be able to define under which conditions (min/max amount) a specific payment method is available if possible. - should include basis setup on our site in order to test it. FTP account will be provided. API attached; there will be a small change added to the API within a week. ## Deliverables see attached API