WHMCS Easypaisa payment module in WSDL

We require to config Easypaisa payment module in SOAP including functioning callback function. the php code is developed. and has been in operation at this moment. but as per demand of the payment module. the merchant account require the plugin to be developed with WSDL services including the callback function following XML responses. - the developer has to confirm; either the WSDL services is running; and including callbacks to mark the invoice as paid in WHMCS. - PHP version of the code will be provided; upon approval; - the freelancer job is to develop the code; along with adding payment in the invoice after completion of payment. default function of add invoice method in WHMCS addInvoicePayment logTransaction checkCbTransID Sandbox account is enabled. the freelancer has to just convert the php cURL method to XML. response. it is mandatory for the freelancer to check the callback;