adding CMFEditions to Plone 2.5.2

Hi,
I'm running Plone 2.5.2, and I want to install CMFEditions.  I'm using a Mac 
running OS 10.4.10.

I did this:
* downloaded the tarball for CMFEditions "for all platforms".
* untarred and put into /Applications/Plone-2.5.2/Instance/Products (where the 
doc says products should go).
* restarted the zope server.
* went to the Plone site setup.

But: CMFEditions isn't listed.  Everything I've read tells me it should be.

Please help me sort this out.

Cheers.
Fil Salustri
--
Prof. Filippo A. Salustri, Ph.D., P.Eng.
Department of Mechanical and Industrial Engineering
Ryerson University                         Tel: 416/979-5000 x7749
350 Victoria St.                           Fax: 416/979-5265
Toronto, ON                                email: 
salustri-6s6ziW1YCwCw5LPnMra/2Q@xxxxxxxxxxxxxxxx
M5B 2K3  Canada                            http://deseng.ryerson.ca/~fil/