I've searched but with no success, I need to add a 3.5% fee to Paypal buyers if it's a B2B sale, basically depending on the customer group. I've seen a lot of solutions to pre 2.3 but very few to a version after that, and even less that depend on costumer group. I checked some extensions but the ones I checked worked fine with all payment types but All-In-One never show to add a fee.
Basically I don't even know where to start. Am I seeing this the wrong way? Any solution to this?
Best regards, Rui Silva