[Zope] Zope 2.7.0b1 - No New Product in Control_Panel/Products and other questions

[andre]

I installed Zope 2.7.0b1 on Win XP Pro
No problems occured during installation of Zope and Instance Home.
I'm able to run both Zope 2.6 and 2.7 on the same machine using two 
different port numbers.
I tried to test a 2.6's product of my own on 2.7.
I copied the product in instancehome/Products and after having restarted 
the server, nothing happened.
The product doesn't appear in Product list;
no error messages,
no special logs,

I added a __init__.py module to the product directory.
Same behaviour

I copied the product in ZopeHome product directory
I was unable to connect to the server.

When i write a products directive in zconf :
products $INSTANCE/Products
i'm to connect to the server.
When i uncomment the line, no problem.

Finally i'm actually limited to products delivered with Zope2.7.0
Great but not enough :)

I have no problem to run the product on Zope 2.6.

Is there something special to do to install a product on Zope 2.7.0

Does Z2.7 use new style classes of Python 2.2.3 ?

Is using interfaces with Zope 2.7 a good way to prepare a product to be 
ported to Z3.
Is there another particular interest in using interfaces in Z2.7 except 
the above one and for documentation purpose ?

Thanks,
Andre