It would be great if there was a built-in solution for SEPM to send an email when new definitions have been downloaded or when it has failed. What we have done is the following:
1. I created a notification alert to send me an email when the SEP client on the SEPM server is out of date. We update only once a day, so this alerting solution has proven effective for us.
2. I have also configured a silent liveudpate scheduled taks to run a a later time at night in case the built-in SEPM Liveupdate fails to download the 32-bit AV defs when it's scheduled to.
Hope it helps....