modify screen 4900 of program SAPMV45A (VA01, VA02, VA03)

[fasihullahkhan]

I have appended structure to add field in table VBAP. Now, I want to add this field in the table control of Sales tab of order screens (VA01, VA02 & VA03) of particular order types as below.

It is still a long shot as I am stuck on screen painter, the field I have added is appearing greyed out like this

Before, I didn't have developer access and object access keys, now I do. But it hasn't made a difference. Please tell me how can I make it work. Which PAI and PBO modules to work with? So far, I have tried following this link

https://community.sap.com/t5/application-development-discussions/how-to-add-extra-column-at-va01-lin...

I am using S4HANA ON PREMISE 2021 02 (05/2022) FP SAP S/4HANA 2021