When you say it's not installing, is it attempting to install and failing on the client, or is it not even attempting at the client and you know you need it through win update?
If it's the former (failing), when I've had this redownloading/redistributing the update usually resolves, and if it doesn't it's because the PMImport was looking for previous version (requires ticket to fix).
It's working ok for me (we're win7 32bit).
On your server, navigate to where patches are stored and look at the MS12-078 folder. For me, this was a new patch in December not a re-release. In any case, make sure the folder modification dates are Dec. You can also try redistributing the patch to have server redownload the files.
In the policy, advanced tab, are the updates checked (I have 4, might be diff if you're 64 bit)?