Hello Geert,
Perhaps its possible to read the MS os and office licenses from clients and put them in the DB.
The keys are stored in the regsitry as an binary value.
With some calculating these key can be read as an normal cd-key
More info and an example VBS you could have a look at http://www.vbshf.com/vbshf/forum/forums/thread-view.asp?tid=322&posts=3&start=1
Greetings Barry