Other things to check are looking at the Help menu in outlook, do you see "About Enterprise Vault"
If that is there, that means EV knows that the user is enabled, it may just be the desktop policy hiding the buttons or the buttons arent being displayed because the tool bar is over crowded
another one to look for is RPC over HTTP restrictions, as the client by default is set to be disabled if Outlook Anywhere or RPC over HTTP is used within outlook
You can confirm this by going to
C:\Documents and Settings\[userID]\Local Settings\Temp and then opening up the latest EVClient log file and it should say in there why the extensions are being disabled
https://www.linkedin.com/in/alex-allen-turl-07370146