IPS Signature not found

Hi, We are running SEP12 RU4MP1 in my environment. We constantly update the IPS policy. There is an IPS signature file that came out 7days ago, however we still cannot find it on the SEPMs when we want to add it. What could be the cause that we cannot find it on the "Add" IPS Exceptions list. Please assist. Here is the link of the IPS signature file: http://www.symantec.com/connect/blogs/patching-windows-http-vulnerability-should-be-prioritized.

Here is the IPS signature:Web Attack: MSIE CVE-2015-1635 

Thanks,

MabundaG