[Zope] VHM Question

I have a Plone site (I know...this is the Zope list, but I don't think that this is a Plone question) named 'intranet'. I want to use VHM to resolve intranet.yyy.com to this folder. Zope is currently listening on port 80 and Apache is not being used. I have creates a VHM mapping which reads intranet.yyy.com/intranet This causes intranet.yyy.com to resolve to the root of my Zope installation instead of to the intranet folder. If I enter intranet.yyy.com/intranet I get to the right folder. Clearly, I'm doing something wrong...can someone please tell me what it is. Many thanks in advance. Marc Stein