FRA-NRT on LH A380
I'm a lucky man, because I booked an UA-firstsaveraward on LH from FRA to NRT on the A380. I booked it online 4 days in advance, and it worked fine.
On the flight back I was on NRT-MUC, and I was able to rebook this flight via FRA one day in advance. ( the rebooking didn't work online just per phone)