Togue, we tried it in the aircraft. With the APU running, we turned off the batteries and had a look at the ECAM ELEC page, where it shows the DC BAT BUS in crosses. STATUS page shows APU BAT START NOT AVAIL. APU FIRE DET was not part of the inop system as I would have expected similar to the DC BAT BUS FAULT.
Stone, The ADIRS were on when we tried it out. Aircraft was in transit.