With SCCM 2012 SP1 there is a problem with the certificate for the MicrosoftPolicyPlatformSetup.msi file.

In the case of OSD and task sequence there is a solution.

Since the KB that is avalible for fixing this is availible via WU and then possibkle to use in SU the patch can be downloaded and added as an offline patching efter the image and before the SCCM agent setup.

http://support.microsoft.com/kb/2749655