Where are you trying to add a system DSN to? Are you using host profiles with AutoDeploy?
I have a full PowerShell script that will help with your vCenter install and creates a system DSN for SQL. http://vexpert.me/Derek55 Check out Part 8, which has my Toolkit script. You can easily parse through the script and see the PS commands to create a DSN.
Thank you, DSeaman, but i need save in the DSN the username and password to login into database. I don't know if it is posible, but it's necessary because the vcenter service doesn't start until you set the user and pass into DSN.