To get Formidable to work with different 3rd party gateways requires a custom solution. Specifically, the developer needs access to the Moneris gateway API. The Moneris gateway API appears to be well documented and has many PHP code examples, which is what you need for integration with WordPress/Formidable. This assumes you are entering the purchase details directly into a Formidable form. I'm not sure how this would work if you are using any of the Moneris pin pads.Without further research, I don't know how you would capture a pin pad's data stream. Another requirement you must be aware of is the necessity of complying with PCI Security Standards. If you take on the job of capturing credit card information in a form, your server and site must be PCI compliant and you must have a process in place for addressing data breaches. To learn more, please see https://www.pcisecuritystandards.org/. This is a lot of work and not a solution that can be provided by community volunteers in forum responses. This is a project that requires an ample budget to complete. Don't be surprised by sticker shock if someone quotes you as much as $5,000 USD or more if you want a complete add-on and encryption of the CC fields in the database. My suggestion is to search the Formidable Masterminds Developers Directory for a resource that may be able to help you.