WIN32_UninterruptiblePowerSupply

I have ten Windows 2003 Servers, supported by 4 APC UPS units.
I have written a simple routine to monitor the UPS units, and shut-down the servers attached to each, as and when necessary.
MSDN tells me I should be able to read more than 40 properties of the UPS unit, by using WIN32_UninterruptiblePowerSupply, but I find I can only read the basic info, namely EstimatedChargeRemaining, Availabilty, Status.
Can anyone show me where I am going wrong?
Here's the relevant code:
[code]
Set colItems = objWMI.ExecQuery("Select * from WIN32_UninterruptiblePowerSupply")
For Each objItem In colItems
Text2.Text = objItem.EstimatedChargeRemaining & "%"
Text3.Text = objItem.Availability
Text4.Text = objItem.Status
Next

[\code]
This works OK, but not if I try to read virtually any other property.

Any clues, anyone?