I've been trying to follow your advice for the first part of this answer, RenjonlynC, but it's not working for me.

Specifically, I would like to be able to print Payment Vouchers that look exactly like the one in your example (with the "Prepared by" and other fields). But I'm unable to see how to make that happen in the template-editing process. 

As you note, the templates are oriented to our own sales forms. Even so, I'm not seeing any options in 'Design' that enable me to show these fields on a bill. I did try adding some fields in the 'content' tab, but those didn't show up on the bill I selected for saving and printing (which, unlike your example, is entitled "Remittance Advice" and not "Payment Voucher."

Are there some steps I'm missing, here?