How to add a new field to the PO-PCC-ORDERS metadata

Dear all,

On the Purchase Order you have the Confirming Order field when you open the PO and go to Terms. This field is not visible in the Orders dashboard from Procurement ECC.

I want to add this to the Metadata, but I'm not sure how to manage this. Can someone help me with providing the correct steps. I tried to enter the attribute key (CONFIRMING_ORDER_FLAG), but not sure if it's correct value or if I need to perform any other steps? I also re-run the Metadata load and Full load, but without succes. I can see the field, but it remains empty in ECC with no values.