I can poll this, but the value returned is always 0. Anyone else having any luck with this? There is a post on the HP IT Resource Forums from 2007 with the same issue, though it remains unanswered.
CPQHLTH-MIB:cpqHeFltTolPowerSupplyCapacityUsed
OID 1.3.6.1.4.1.232.6.2.9.3.1.