[Zope] Query on CMF.

Hi, I am having zope 2.5.1( Windows 2000 platform) and was trying to add CMF1.3 to it. But even after copying it into the products category of zope, its not getting reflected in the selection list or in the products list of the management console. I have tried restarting zope but still its not working. What might be the reason? Expecting an earlier response. Thanks and regards, Paul.