Integration with Salesforce

When the transaction is completed on Moneris Hosted Pay page, the HPP generates a Post request with the transaction confirmation id and sends it to the Approval URL selected on the configuration page. Is it possible to add a security token (auth token by Salesforce) to the POST request generated from Moneris before sending it to Salesforce. 


Broadly, this question is - Has anyone been successful in integrating Moneris with Salesforce without any third party layer?