As of Release 4.0A, you can maintain an assignment between FM account assignments (funds center, commitment item, fund) and sales document items (order items). The FM account assignment is passed on to follow-on documents (billing document, goods issue, purchase requisition, CO settlement).
If you want to use the above-mentioned function, you must use Funds Management Customizing to maintain a field status (required, optional, hide) for each FM account assignment.
You can find more information on this in the Funds Management implementation guide in the section "Maintain field status for assigning FM account assignments".
If you have maintained a field status, you can maintain the assignment in the sales and distribution document under Item data -> Account assignment -> FM acct assignment. The incompletion check is fully available for the FM account assignment.
Default values can be generated from other account assignments or from a user exit.