Interesting... Some people have said SAUA availability is I and some have said Z, within this thread and others.
Aeroplan agent couldn't do anything to check availability. EVA agent said they can't see SAUA availablility and said Z was not available. Still not bookable via Aeroplan or Asiana. EF and KVS show I availability and CS+ respectively; in these circumstances, I could have easily upgraded via Aeroplan already. Not sure what's going on.