In order to install/configure WSUS to be used with SCCM 2012 SP1 on Windows Server 2012, perform the following:

1. Add the WSUS server role. Once the installation completes, cancel the WSUS configuration wizard, as we’ll be configuring the WSUS through the SCCM.
2. For Windows Server 2012, there’s no need to install the WSUS 3.0 SP2 or any of the previously required KB2720211 or the KB2734608.
3. Proceed to add the Software Update Point site system role in SCCM.
4. Once completed, either manually initiate the Synchronize Software Updates through the SCCM console or wait for the scheduled sync if configured. Please be patient as it could take some time for the initial catalog to load up. However, there are couple handy log files that could be used to ensure things are on track and there’s no sync errors. The log names are WCM.log and wsyncmgr.log
5. As far as there are no issues in either of the above mentioned logs, and with some patience, you’re going to start seeing the software updates in the Software Update Catalog in your SCCM console.