Build me a custom WHMCS Payment module

I need a custom stripe module for WHMCS. I know WHMCS has a built in one but I need a custom one because I am using two WHMCS installations. One is a real site and the other is a dummy site. I need everything to be processed on the dummy site but once the payment is made, send the details to the real site so that the invoices are marked paid. CC info needs to get stored for clients and recurring payments should also work.