Inasmuch as AA permits a free, five-day hold on award reservations -- even for an AAdvantage member who does not then have sufficient miles in his account to pay for the award redemption -- the OP can call AA, reserve the necessary JL/AA flights (if available), and then purchase the required additional miles, which should post well before the five-day hold expires. After the purchased miles post, call AA back and ticket the held award reservation.
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