PayPal API certificate

Hi guys, I'm looking for some assistance with the PayPal API please (Express and Website Payments Pro). I have installed these modules a million times before. However I have now need to enable these modules with an API certificate instead of an API signature. Does anybody have any experience with configuring these modules with a certificate instead of a signature? There seems to be very little in the way of documentation online.

Thanks

You may have to conact Paypal about a certificate. Their developer site can give you other forms of information (eg client ID) to interact your site but I don't know much about how this works so sorry.

As far as I searched the Paypal modules that come with Opencart are only able to use Signature, not Certificate. Someone (or me?) may need to come up with a new Paypal payment module for Opencart 2 that works with Certificate-based authentication. Until then the only solution could be to change your Paypal account so all your Paypal integration to use Signature (because you can only do either Signature or Certificate). If someone knows of a Paypal payment module that can work with Certificate please let us know otherwise if you need one please indicate so community can gauge this need and maybe a module will come up. All of the above assuming my brief looking into this issue is correct. Hope it helps!

http://www.opencart.com/index.php?route ... n_id=24660
DEMO: http://demo.ilithemes.com/oc2031/index. ... duct_id=59
This is a regular product which can be used with this payment method, the others have recurring profiles...