Membership – How do I add a custom PayPal button with drop down implementation into the membership r

In the Membership plugin I created a subscription plan and setup the payment gateway as a Paypal single payment gateway. Now I want to swap out the button for a PayPal dropdown button that I customized in PayPal, however I don’t know where to find it within the Membership plugin to swap it out. Since this button is auto generated in the registration/joining process of the site, I’m not sure where to swap out the code with PayPal’s auto generated code for the button.

Thanks, Curtis