Order type related order reasons

In VA01 main screen we want to populate ORDER REASONS only specific to ORDER TYPES i.e different order types will have different order reasons in the dropdown list.

I have searched the entire forum and got to know the below solution :

"we can use user exit MV45AFZZ & use function module MOVE FIELD TO VBAK. Default VBAK-AUGRU field to order code for the selected values you want"

However, this ONE is NOT working properly...The data is still taken from the SPRO Order Reason table and not from our Ztable. Dont know why !! but we think the Program is incorrect for VA01.

Also we have done it in ADDITIONAL DATA TAB B but Client wants it in VA01 MAIN SCREEN ONLY.

Is there any way out !

Please revert ASAP