How easy to setup PayPal Payments Pro even though that wasn't set up initially in eCart?

Client has decided that they want to use PayPal Payments Pro after all. How easy will this be to configure now that the payment pages are all done?
www.dreamcargalaxy.com

In the past I would have set this up through the eCart wizard so now I'm not sure what to do. :(

Appreciate any advice/guidance offered.
Thank you.
NJ

I think you could run the wizard separately and create new pages and you should just have to replace the confirm.php page. All of the code for checkout should be on that page and you only have a button on the page now, so it shouldn't interfere with the other updates you have done.

Just make sure you don't overwrite any other pages.

What pages does the Checkout Wizard create?
checkout.php
checkout_failure.php
checkout_success.php
confirm.php
confirm_cart.php

Right?

So, I should maybe rename all these with a suffix and run the Wizard again selecting the PayPal Payments Pro option, then compare both files and only update what's missing in my previous files?

What if the client changes their PayPal Payments Pro details. I won't have to run the wizard again in order to change these, will I?

Thank you.
NJ

The credentials are saved in a separate include file.

The only file you will need to change is the confirm.php page. It is probably a good idea to back up all of your pages first, but the wizard does allow you to use different page names.