Microsoft SMS for software audits

I’m running MS Sytems Management Server for Hardware & Software inventories on our network, but I need to get the MS Product IDs for Windows 2000, MS Office 2000, MS Access, etc.
SMS does not collect this type of information by default, but I’ve read that you may be able to modify the schema to allow other inventory information.
Does anyone know of any third party utilities that will add this feature?
Any info will be helpful.
Thanks.