New Feature in MDT2012 allow you to deploy a Group Policy Object (GPO) Pack. Now that SCM 3.0 Beta now available to support Windows 8. (More info here and here ) You need to tweak the script to enable the support for deployment of GPO for Windows 8
Build your local local GPO based on SCM 3.0. You can find additional resource about SCM at http://technet.microsoft.com/en-us/solutionaccelerators/cc835245
Export the Baseline you built or the default one using GPO Backup (Folder) option from Export Menu on the right hand corner
Navigate to the following directory in your MDT folder <Distribution Share>\Templates\GPOPacks\Win7SP1-MDTGPOPack
Copy the following files ( GPOPack.wsf, Localpol.exe , LocalSecurityDB.sdb ) and paste it to the exported Windows 8 GPO Folder ( Make sure you name the folder as Win8RTM-MDTGPOPack )
Use any script editor and open GPOPack.wsf from Windows 8 GPO folder and look for the section where it validates the Windows 8 and edit the file as per the below instruction and save it.
Modify the lines to the following
If(Left(strOpVer,3) = "6.2") and (strProductType = "1") then strOS = "Win8" Elseif(Left(strOpVer,3) = "6.1") and (strProductType <> "1") then strOS = "WS08R2"
Now you are ready with your default base line package. Copy this back to the Template folder in your workbench
Update GPOPackPath variable in the customsettings.ini file to point to this new GPO Pack
GPOPackPath = Win8RTM-MDTGPOPack
If you do not want to apply any GPO Packs then task sequence step can be skipped by setting the variable ApplyGPOPack to NO in customsettings.ini.
Open the MDT Task sequence , Make sure you have the step exist to launch the ZTIApplyGPOPack.wsf called. ( This is part of default client task sequence) or you can manually add a “Run Command Line” Step after Restore Groups
There is no need to edit ZTIApplyGPOPack.wsf since the entry for Windows 8 is already present