Why do you want to put in the AA number? The
rules do not allow you to benefit from doing so.
you cannot redeem partner airline miles with your partner frequent flyer number and obtain AAdvantage program benefits such as Priority boarding (Group 4) and access to preferred seats.
This has been covered extensively for years on blogs and FT:
News To Me: American Restricts Elite Benefits On Partner Award Tickets
American Airlines Is Preventing Elites From Using Their Benefits on Partner Award Flights
Assign AAdvantage Number to BA Award Booking on AA?
Adding AA # to flight book with AS miles