Update VBKD-IHREZ field in MV45AFZZ Exit on price redetermination

Hello Experts,

I want to update VBKD-IHREZ with a value everytime I do update pricing in a sales order.

I am able to update VBKD-IHREZ while creating sales order.But when I change the same sales order and redetermine the price my logic in MV45AFZZ doesnot update VBKD-IHREZ.I have tried to put in logic in USEREXIT_SAVE_DOCUMENT and USEREXIT_MOVE_FIELD_TO_VBKD also but not able to update vbkd-IHREZ on price redtermination in a sales order.

Kindly provide me with your suggestion on how this can be achieved.

Thanks

Vijaya