Vault Cache Indexing and Search
Include the full message contents of the vault cache in Windows Indexing searches.
See cases 04468707 and 04320745 and and the below detail from http://www.symantec.com/business/support/index?page=content&id=HOWTO84085
Windows Search (WS):
Windows Search can be configured to index the Vault Cache including both the Content & Header Cache (MDC) to provide a single search solution for finding a users data across the local file system, Outlook cache (OST) and EV archive.
As Windows Search is searching in both the Content & Header Cache (MDC), Windows Search will be able locate data within both archived email content and attachment content.
Which seem to be inconsitent.