As long as the fare class is eligible (http://www.aa.com/aa/i18nForward.do?...kaAirlines.jsp) I'd suspect just quote your AA FF number when making the booking with AS. And then keep your boarding pass in case it doesn't post after the flight and you have to follow up.

EDIT: Just saw that maybe you've already flown your AS flights, in which case you won't be able to transfer already earned AS miles to AA.

BUT if you transfer 100,000 SPG points to AA, with the 5,000 bonus on each 20,000 transferred, you'd end up with 125,000. Together with your existing 75,000 AA points, that should give you enough for a J RTW award.