Not able get the control to change Screen fileds proprties scree exit QA01

Hi,

I am workig on Screen Exit for QA01 Transaction.By using Screen Exit i am able to add custom Fileds as per requirment.

data is also populating. But the problem is added fileds are in editable in QA03 Transaction. In Subscreen PBO and PAI i define

modules.In that module i set one break point. System is not trgeering that BREAK-POINT. SAP given two function Exits for PBO

and PAI. In PBO function-exit

LOOP AT SCREEN.

ENDLOOP. while Processing added fields are not populating in screen Stucture.

Can any one Suggest me How do i get the Control on Screen Proprties Change in Subscreen added fileds.

CALL CUSTOMER-SUBSCREEN USER0001 INCLUDING 'SAPLXQPL' '0100'. EXIT:QPL10004

Thanks in Advance....

regards,

kishore