Exporting positive pay file with a .csv extension

The previous posts were about AX2012 using AIF ports, which is why I'm creating a new question.

Is there a way I can export the positive pay file with a .csv extension instead of .xml? I know I'll need custom code for this, but I'm struggling to see where I can create a post-handler or extension for this, since there are two ways you can create the positive pay file (periodic tasks and through the bank accounts screen).