Thanks, BuzzBox... I should probably read the report (*^ ^*). From the initial posts, I didn't get the impression that the F/O knew what he was doing. I recall that on the 744, if you have one IRU in NAV and the others in ATT, the IRU in NAV will feed magnetic heading data to the IRUs in ATTitude (I can't recall if the HDG entry boxes still appear with one IRU still in NAV).
Of course, we are talking about an Airbus....