Hi Dave, I'll take an educated guess at this one, but if it still doesn't work, you may want to seek assistance with your hosting company. From what you are describing, it sounds like you have the mojoPortal pieces in place (new site, with a new subdomain assigned to it via Hostname Mapping).
You should go into your hosting DNS settings. You will want to make a new entry for www.raleigh.norulesworld.com, pointing to the same IP address as www.norules.com (if this is not shown in your DNS settings, you should be able to determine it elsewhere). Once that is in place, then incoming requests will be directed to your mojoPortal site, and mojoPortal will evaluate the host name and send the request to the appropriate site.
Hope that helps out.