Hi Brian,
You won't be able to dump the code onto a Method screen, but you should be able to accomplish this with Method actions. If you are just looking to add a PayPal button that takes you to a specific URL, you can add a Picture object to your screen and use a Load Web Page action on it. This will make the picture clickable, and take your user to your PayPal page.
We're currently working on integrating directly with PayPal. Should be available soon!
Jason