Just read the FCOM 7.10.3
Option:
A-TO1. A-TO2 - APU to pack or APU to pack derated
I guess that we didnt buy that option!
In 1997 when we were selecting the aircraft, we had long discussions with Boeing FLOE regarding PACKS OFF takeoff for additional weight with the APU providing air conditioning, it wasnt possible for the reason that i stated above!
Sorry about the mis-information.
Mutt