Proliant Servers - Missing WMI value - IdentifyingNumber

[ton182]

Hello,
Having some problems with 6 HP Proliant servers we have on our network. The problem I am having is that they are not reporting their serial Number within WMI, which in turn is making SMS/MOM not report this informaiton on our asset database.
I have been searching on net but not come across anything that seems to help me.
The WMI object that SMS queries is the objItem.IdentifyingNumber and when I run a script on one of the 6 servers the value is blank. When I run the query on anotehr server that reporting back it works fine.
The script I am running to get the Values back is:
On Error Resume Next
strComputer = "."
Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
Set colItems = objWMIService.ExecQuery("Select * from Win32_ComputerSystemProduct",,48)
For Each objItem in colItems
Wscript.Echo "Caption: " & objItem.Caption
Wscript.Echo "Description: " & objItem.Description
Wscript.Echo "IdentifyingNumber: " & objItem.IdentifyingNumber
Wscript.Echo "Name: " & objItem.Name
Wscript.Echo "SKUNumber: " & objItem.SKUNumber
Wscript.Echo "UUID: " & objItem.UUID
Wscript.Echo "Vendor: " & objItem.Vendor
Wscript.Echo "Version: " & objItem.Version
Next

So is there anyway to add the IdentifyingNumber on these HP servers.
5 are running Windows 2000 (and have been in the field for 3-5 years), and the other one is running Windows 2003 and is only 6 months old.

Look forward to your replies (sorry if I have posted this in the wrong subject).

Tony