I have created an enrolment plugin for "PayWay" payment gateway, adapting Paypal enrolment plugin. It looks something like this...
But for Payway to work, I also need to upload a certificate to connect with PayWay. This certificate is a file that will need to be uploaded, so I would like to add this to the interface as well.
In settings.php in paypal enrolment plugin, I found:
So I need something like
but I didn't found a function like this
Can anyone give me a hint on how can I do this?