Integrating PMPro with external payment gateway

Hi guys,

I am trying to integrate a payment gateway that I have set up with PlugnPay and a PMPro installation on my wordpress site.

I have the PlugnPay instance running on a subdomain and I am looking to utilize an API of sorts to allow payments made through this instance to be recorded for monthly subscriptions on PMPro.

I am trying to avoid integrating PlugnPay directly into WordPress and the PMPro page, I was able to accomplish this with Woocommerce since they have a readily available api that I can use to retrieve information while processing payments on the subdomain.

Any help would be welcomed, I just need to be pointed to the right path.