You can launch Enterprise Vault's Archive Explorer from the button on the Outlook toolbar, but what if you don't or can't allow the button (for some reason)? You can remember the URL, and put it into Internet Explorer.. or you can do something a bit slicker, and launch Archive Explorer off a folder from within Outlook. I'll explain how :
Create a new folder in Outlook
Any name will do, and leave it at the default of Mail and Posts for the type of items in it.
Now click on the folder and go to the properties
Click on Home Page
In the Address dialog put in the URL in a similar manner to this : http://evserver.ev.local/EnterpriseVault/ArchiveExplorerUI.asp
Tick the box saying to show the home page by default, and click OK.
Click on a different folder, and then back to this one.
Hey presto, you'll have Archive Explorer launch inside Outlook from your folder (with your navigation bar of folders still visible too)