Default field that is hidden on the form

Hi,

I’m trying to set the default value of a field that is hidden on the form. I don’t want the end user to have to see the field on the form so it’s hidden. It’s an Option Set data type and I’ve added this to the shortcode, but it doesn’t appear to be working and does not set the rvr_leadsource field value.

default=”{rvr_leadsource:Corporate Website}”

Any ideas?

Thanks,
Sally