One of the things which was noted in the most recent Compatibility List updates was that Enterprise Vault now co-exists and works with Exchange 2010 SP 3. This was an update from Microsoft which, as well as fixing many issues, allows co-existence of Exchange 2010 and Exchange 2013 in the same Exchange organisation. So the fact that Enterprise Vault now works in this same environment is great.
It's worth noting that the support/certification matrix includes a small caveat around the running of the Enterprise Vault Throttling Script. This is the script which releases the throttling that Exchange imposes on a regular 'user'. It's necessary because the Vault Service Account needs to act in a way as a 'super user' and not have limits imposed on it relating to connections to Exchange and so on.
The article describing the issue with the throttling policy is: www.symantec.com/docs/TECH205513
