Validate screen fields in SAP GUI(ME51N) which are added from 'Custom field and Logic ' Fiori App

Hello All,

Custom fields are added from Custom field and Logic Fiori app into Purchase Requisition. These fields are automatically replicated into back-end tcode ME51N as well.

Now, I need to validate these fields in back-end based on PR status.I tried F1 and found CFD_SAP_GUI function Group is generated into back-end side but there is no PR details in this. Only Fiori fields are there.

Please help!!