I am trying to book a flight from SFO to FRF next fall. I want seats in the 747-8 upper deck. Lufthansa won't let me see seat availability until after I book the flight which locks me in with a flight where the upper deck seats are not available. I have tried United and other booking sites and still can't see what is available in the upper deck. Is there some trick to getting this information without being locked in to purchasing the ticket first?

Thanks,