Ah, there's the problem. Needs to be on ODO, not Trip A/B.
Page 122 of 2004 manual:
1. Press the “POWER” switch to the
“OFF” mode with the odometer reading
shown. (For details, see “Odometer and
two trip meters” on page 115.)
2. Press the “POWER” switch twice [without pressing the brake] to
select the “IG–ON” mode while holding
down the trip meter reset button.
Hold down the [trip meter] button for at least 5 seconds.
The odometer indicates “000000”
and the light goes off.
For step two, be sure you are not pressing the brake pedal, or else you will go to READY, then Off, rather than ACC then Ig-On.