Hi OCP
Could you please go to Sales register and click into one of the applicable invoices > Print > Preview, select the desired custom form, does it show the information you are after? If it does, then please check to ensure this form is set as the default form for this transaction layout via Print/Email invoices > Advanced filters.
If the preview doesn't show the information either, I'd suggest editing the form via Setup > Custom form to verify that the correct fields are in place. You can always remove then add the fields in, or create a new form by adding a How to pay section to it then set it as the default. Alternatively, you can set up Online Invoice Payments which also covers BPAY.
