Dolibarr 13.0.2 - New action

Hello to dolibarr forum!

I would like to ask about dolibarr version 13.0.2 and triggers.
More specifically, I made a new interface file with 99 priority (my file example: interface_99_modAgenda_MyName.class.php) with only one action and this action called when a new invoive payment being generated (@paiement.class.php).

My problem is that, when i fully pay an invoice, the action which been called is BILL_PAYED not my custom action. I followed your dev documentation about triggers and I can not find a soution to my problem. I would appreciate your feedback.

Thank you in advance!