P31113 - How to automatically select the lot number based on on-hand lot date during issuing materia

 Hi, Currently we have to manually assign the lot number at issuing matrial. Otherwise, the system will give error message "Lot Number must be entered". What we would really like is to let the system assign the lot number based on on-hand lot date. Any suggestion? For example, for component A, Lot A with on-hand date 10/1/2010, lot B with on-hand date 10/31/2010. We want the system automatically pick lot A instead of manually selecting the lot by user.