How do I generate a csr that uses the SHA-2 algorithm?

I asked the question of my Symantec rep. This is his answer:

"You are right, the CSR will default to SHA-1. Below the CSR, there is the option box with multiple options with the first one defaulting to SHA-1 but there is an option right below in the option box that will show SHA-256. You will see the option box right below when submitting CSR and you will have to manually choose the SHA-256 option."

So with that question answered, I'm wondering if I apply a SHA-2 certificate to my websites, how many complaints will be generated by users who are using some oddball boutique browser?