You would search for both Qantas and JAL availabilities on Iberia's website, not BA's, but you may find BA more useful to find certain flights. I can see Qantas on Iberia's website fairly easily, I only tried a few JAL services and couldn't find anything specific but there again we don't have your routes or dates, so I can't be sure there. Iberia needs TYO as a code rather than Haneda or Narita. If all else fails then you will need to call up.