Thank you Jason,
That is what I was hoping for. We do have two fields on the checkout page already that we would like to pass to the gateway so it sounds like we are half way there. There are two fields that are toggles "Pick up" and "Delivery". along side of that is a date picker field. We would like the gateway to show that the order was "pick up" or "delivery" and the date the customer has requested.
I have attached the files, what or where should be my next step?