Product bundle (Child Items serial number) in POS

hi there,
i have set bundle product A as Parent item B .(B is Child Items of product A).
item B have serial number and batch number.

problem is if when i sell product A in POS , POS not ask serial number for item B, how ever if item B sell in POS , it will ask for serial number.

how can i make parent item A ask for serial number item B in pos?