How to change default JRun error page

I'm running CF9 with Apache 2.2 and I can't figure out how to change the default JRun error page. So if CF is down or rebooting I'd like to redirect to a nice error page instead of the default "Server Error Could not connect to JRun Server" error page.

I know in Apache you have to change the following line...but it's still not showing up for me. Is there something else I'm missing?

JRunConfig Errorurl "http://localhost/serverDown.html"

I've tried without quotes, url=, etc but I still can't get it to show up. Can anyone point me in the right direction?

Thanks for any help.