How to track Microsoft CALs and software downgrades.

Currently i find it very difficult to track MS licenses in Servicedesk.

Can somebody please explain how to track Microsoft user or device CALs

For example lets say:
We have a ms open licenses for 100x 2008CALs and a other for 15x 2008CAL.
Need to track license per seat.

In assets add software license, license type is Client Access License
This i do understand, but what to choose on Managed Software.

I can not figure out how to easily track CALs ?

Second problem:
I have for example a Microsoft licenses for 5x Windows Server 2008
But actually installed 3x Windows 2003 and 2x Windows Server 2008. (Making use of MS downgrade option.)
Actually same goes for office or client operating system licenses.

Also i find it a problem that you can not edit and change the Allowed Installations on a license.
I want to use this option for hyper-v hosts, where you can have for example a windows enterprise license and this allows 4 installed virtual machines + one 'free' license on the host itself.