after being initially denied by the agent's helpdesk ("we don't request seats from other airlines") I persisted and explained to them I had got AA to successfully request tickets from Qantas before when they had a massive schedule change. Fortunately, she persisted with her helpdesk and they managed to send off a request a J seat on a connecting JL flight to the JL oneworld liason (which had no J award availability). A few days later, I received the eticket confirmation with the new flights.