Thank you Jeff.
I took a peek at both solutions, and neither was too easy to understand for someone that's not into this kind of scripting against OCS and AD. I will take a better look into it tomorrow, and I believe I could make it work with some testing and sweating.
It's a pity this isn't a built-in feature, when it's possible to to modify other attributes for multiple users at the same time, such as enabling/disabling Federation and Public IM Connectivity.
Regards,
Anders