Hello dominik,
I'm currently packaging Office 2010 MAK with the OCT (Office Customization Tool) that works fine.
The key is well registered and Office is auto-activated.
Here's what i've done :
1° go to the Office 2010 installation folder and run the setup in administrative mode :
\\server\share\Office2010\setup.exe /admin
2° the OCT opens and let you manage what you want to install (some screenshot to show you what i've done) :
For this part, originally there's no entry. I've added AUTO_ACTIVATE and set the value to 1. I've also added the HIDEUPDATEUI and set it to True but i didn't notice any difference...
Once every modification has been done, save your MSP where you want, keeping in mind that you will have to copy it in the "Updates" folder of the Office installation folder.
3° Once everything is OK, in my install batch i've wrote
"start /wait %source%\setup.exe /adminfile %source%\Updates\Custom.MSP"
Once the installation is done, the only problem i encounter is the first launch security message that i couldn't hide... but to answer your initial question; Office is auto-activated at all.
Hope it could help.
Yannick.
P.S. We also have a proxy server set by default for all users and i didn't had to care about during the setup or the config...