On v.3, it was possible to select a payment system on the product configuration, forcing that product to only work with one payment system. This was very important to me, as I need to have more than one payment system for different countries, but cannot let the user select (they get confused and don't know what to do). On v.4 I see that it's possible to remove the payment system brick off the signup form, but I don't see how to associate a product with a single payment system, as there's no such option on the product configuration. Is it possible to force the payment system to each product on v.4?
nevermind... I already figured it out! If someone finds this thread looking for a solution for the same problem, you change the payment option editing the brick on the form. It's not as straight forward to figure out that you can click on the brick to edit it, at least it wasn't for me!