Ability to use just the hostname in the proxy services

We have a client where the users are used to only typing the hostname and the domain name is appended by the workstation configs.

So, we need to enable that functionality via NAM.

I tried using just the hostname in NAM, but NAM would not let me. When I type just the hostname in the browser, I get a NAM 403 URL Tampering error.
I found a cool solution for error.jsp page, which talks about redirecting to the FQDN using a javascript, if just the hostname is specified in the browser.
Cool Solutions: Redirecting the Access Gateway to the Full Domain Name

I tried that setting in the error.jsp page, and it took me to a namproxyfailover error page. There isn't any proxy service defined for namproxyfailover. So, I am wondering, what might cause this page to be rendered. I even tried specifying redriection to Google to see if NAM would redirect to a third-party page (window.location.href = "http://www.google.com";). That did not work either
Is there any other way that I might be able to implement the redirection?


Thanks