I would like to develop some payment modules specific to the African continent and I would need your help, including a plugin for Western Union.
I explain the principle which is quite simple overall.
I have already done a part of the backoffice, I added fields Name, First name and telephone number of the seller.
A customer places an order, so he chooses Western Union, he goes to Western Union, proceeds to the payment by notifying the surname and phone name of the beneficiary.
Western Union gives him a transaction number, the buyer communicates it to the seller and the transaction can be done.


What I can not do is from the selection of the payment method, when we come to the page 'payment.html'
This information is displayed and an input field is present to insert the transaction code.

Code of course that we record and which must be visible from the backoffice on the order.

I'm trying to write my code in:
function PCPbeforeProceedToPayment
Is this the right place? Because nothing is displayed
Thank you for your help.
Regards,
Thierry