1. The first step is to update your WSUS server to SP2. If it is not already installed, download Windows server update service 3.0 SP2 Windows Server Update Services 3.0 SP2
2. Install Windows server update services 3.0 SP2 on all machines that you have the server database or server management tools installed upon
Note: If prompted to set the WSUS website TCP port number make sure that you use the same TCP port number previously configured.
Note: If prompted to uninstall the previous version make sure to keep the database, files and configuration data. Then once the uninstall has completed re-run the installer
3. Install Windows server update services 3.0 SP2 update KB2734608 on all machines that you have the server database or server management tools installed upon
4. Lastly you will need to install one more update onto your WSUS sever (KB2734608)
Note: once installed your version of WSUS should be: Version: 3.2.7600.226 (you can find the version within the console under help about.
5. Your Windows 2008 WSUS server will now be able to update Win8 and Server 2012.
6. You will now need to select the products & classifications that you wish to download updates for, this is under 'Options' then 'Products & Classifications'
7. You may wish to force a synchronisation to download the updates straight away. To perform this action right click on 'Synchronizations' in the left hand menu and select 'Synchronize Now'. Once completed WSUS will have the updates available for approval and distribution.