With smartnet you are entitled only to minor upgrades.
Going from 3.3 to 4.x is a major upgrade.
Tac can check your contract and they will publish the software for you
if it's covered in your contract.
Else contact your cisco account team or reseller
to purchase an upgrade.
By the way you can download the acs eval for windows at no cost and try it. Then you could migrate the data over the licensed version.
I recommend you 4.2 version, with latest patches. From memory its build 124.
