Plone and Version Control

[Jon Babbage]

I am looking at building a document server using plone and need
version control.  CMS Matrix
(http://www.cmsmatrix.org/matrix?func=viewDetail&wid=2&listingId=1002)
indicates that plone has document management built in, but I have not
found it if it is there.

I have also found some software
(http://www.emergence.com/WhatWeOffer/products/PVS) that claims to add
this functionality to plone, but have been unable to get this working.

Does anyone have any other ideas for building such a document server,
or has these features working on their own systems?
/jon