Create or customize php for use with external Credit Card Authorization

I need to modify my Memberpress addon to accept my USAEPAY Authorization using PHP on the backend... I have the formula that needs to be written into php , I have attached ther current php for [login to view URL] and also a workaround using an emulator...I just need to either add the USAEPAY php or figure out how to use the emulator. URLs - [login to view URL] [login to view URL] Emulator - [login to view URL] his is a simple thing to do according to my Merchant support but I know nothing about PHP