Field values are blank in PO form after changes are made

Hello,

I have created a Purchase Order form in SFP (Form Builder) using the MEDRUCK_PDF interface.  After I create a purchase order in ME21N and click Print Preview, most of the fields populate. I have Item number, Material number, and Order Qty to name a few. Two new fields I have added, Order Number, KOMK-AUFNR, and Material Group, EKPO-MATKL, don't populate even at creation.

If I go back and make changes to the form in ME22N, when I click Print Preview, several of the fields that originally had values are now blank in the preview and also when the form is printed.

Is there a setting in SFP that needs to be set so the data will be retained after changes are made?

Thanks,

Chris