I am pasting the relevant parts here.
DATA lw_bus000_eew TYPE bus000_eew.
LW_BUS000_EEW-ZZBU = <GS_RAW_DATA>-BU. " Business Unit
LW_BUS000_EEW-ZZSUBBU = <GS_RAW_DATA>-SBU. " Sub-Business Unit
Here ZZBU is added via EEWB and ZZSUBBU is added via AET. The system throws syntax check error saying LW_BUS000_EEW-ZZSUBBU is not defined.
I have cloned the FM BUPA_CENTRAL_CI_CHANGE into a Z one, added one extra structure as the importing parameter, passed AET fields into the new structure and modified LS_BUT000 structure inside the Z FM with this data. This way now I am able to update the data in BP.
What is surprising is that you can update these fields via SE37 but when you use the AET fields in program to pass data on you get the error.
Update: The SAP GUI transactions/function modules does not handle the AET fields by default; we have to enhance the standard code to update the fields when GUI transactions are used. Looks like cloning/enhancement is the only way.
Thanks,
Hashim