Is there a way to change the entry screen when entering an invoice?

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I have designed an invoice. I need to be able to reference multiple PO numbers on a single invoice for a particluar customer. I added a colum right before "Quantity"  in the design format screen, & saved. I can print/preview the template and it looks great. When I go to create a new invoice, the colum is gone, none of my changes come through. The fields are not there for me to add the nessassary information. How do I see the fields on the invoice INPUT screen to enter the information? I now understand that changing the form has nothing to do with the entry screen, which is really unhelpful when I cannot actually enter the information into the new field. Why have the ability to add a colum, then not be able to enter data into it when you try to creat a new invoice?

Is there a way to customize the entry screen? So when I choose a different Invoice Layout, the template I need can be pulled up? I JUST want to add a dang colum and be able to enter data into it. I can hardly see anymore I have been working on this so long. 

Thank you so much for any input. I have been trying to figure this out for hours! I have been using Peachtree for over 15 years. 

Laura