When I started this thread a few months ago I thought it would go nowhere. Multiple emails back and forth with Alaska listens yielded zero. As a last resort I sent a letter to a senior VP in Seattle, with copies of all the emails. Two days letter I received an email from HQ. Turns out all that was required to actually select a seat was to enter the AS code share flight number in addition to the JAL record locator, Of course nowhere in the PNR was the AS code share listed. The email provided me with the Alaska code share flight numbers. I went on the JAL website, went to manage seats, added the JAL record locator and the Alaska flight numbers and voila, the seat map opened and I was able to select seats. A corporate case of the right hand having no idea what the left hand was doing. Sometimes it pays to be like a dog with a bone