If a PO with item category 'L' subcontracting is created, the system explodes the material BOM for the material being purchasesd. In the subcreen for components in the purchase order (as determined by BOM explosion), there is an option to assign batches for each component. I want to make the batch field mandatory so that when the PO is created, the user has to input batches. How can this be accomplished? Help is appreciated, thanks.