Can I add a WinServer 2012 into a mix child Domain with 2008 and 2003?

Question

The founctionall level is 2003 and the main domain is mix with 2008 and 2003. The user need the templete of Server 2012 and use the "new" group policy so that they are able to use the "new" feature in windows 8 (which I totally
do Not think is much useful). I've a plan that join the 2012 server into a child domain as a DC but I don't know if that will cause any problems. Can I do so?
Thanks all.
Gary

Answer 1

@Darren: http://technet.microsoft.com/en-us/library/jj592683.aspx
For Windows 8 a change to how the TPM owner authorization value is stored in AD DS was implemented in the AD DS schema. The TPM owner authorization value is now stored in a separate object which is linked to the Computer object. This value was stored as
a property in the Computer object itself for the default Windows Server 2008 R2 schemas.
To take advantage of this integration, you must upgrade your domain controllers to Windows Server 2012 or extend the Active Directory schema and configure BitLocker-specific Group Policy objects.
Windows Server 2012 domain controllers have the default schema to backup TPM owner authorization information in the separate object. If you are not upgrading your domain controller to Windows Server 2012 you need to extend the schema to support this change.
To support Windows 8 computers that are managed by a Windows Server 2003 or Windows 2008 domain controller
There are two schema extensions that you can copy down and add to your AD DS schema:
TpmSchemaExtension.ldf 
This schema extension brings parity with the Windows Server 2012 schema. With this change, the TPM owner authorization information is stored in a separate TPM object linked to the corresponding computer object. Only the Computer object that has created
the TPM object can update it. This means that any subsequent updates to the TPM objects will not succeed in dual boot scenarios or scenarios where the computer is reimaged resulting in a new AD computer object being created. To support such scenarios, an update
to the schema was created.
TpmSchemaExtensionACLChanges.ldf 
This schema update modifies the ACLs on the TPM object to be less restrictive so that any subsequent operating system which takes ownership of the computer object can update the owner authorization value in AD DS. However, this is less secure as any computer
in the domain can now update the OwnerAuth of the TPM object (although it cannot read the OwnerAuth) and DOS attacks can be made from within the enterprise. The recommended mitigation in such a scenario is to do regular backup of TPM objects and enable auditing
to track changes for these objects. 
To download the schema extensions, see Schema Extensions for Windows Server 2008 R2 to support AD DS backup of TPM information from
Windows 8 clients.
If you have a Windows Server 2012 domain controller in your environment, the schema extensions are already in place and do not need to be updated.
Also, if you check the GPO's in 2012, there are specific templates for Windows8/2012 and specific (legacy) templates for Windows 7.
MCITP:SA:EA:EMA2010:VA2008R2