Here are some important things for you to note:
Support for SQL Server 2005 with Enterprise Vault (EV) products.
http://seer.entsupport.symantec.com/docs/281261.htm
How to move an Enterprise Vault (EV) SQL directory and store databases from one SQL server to another
http://seer.entsupport.symantec.com/docs/273272.htm
Make sure to have good backups of the databases before you start and you should be just fine.
Also, I highly recommend getting EV upgraded asap! You are several versions behind and there are some really nice features you are missing out on.