I'm trying to figure out how to replicate the process for sending Google Analytics campaign data to Salesforce detailed in this blog post: http://www.e-nor.com/blog/google-analytics/integrate-salesforce-and-google-analytics

The example shown is for a simple webform. I'm trying to figure out if I can make it work using VisualForce. Righ now I've only changed the <input type="hidden"> to <apex:inputHidden>. I've had no success using this approach. 

Any solutions to this? Other ways to pass Google Analytics campaign tagging data through my Force.com form? 

Thanks!