[mod_python] Session timeout

I'm debugging an error:

     * id: 80b5b4b9af0a2e710195bab30cc3c358
     * is_new: False
     * created: 1164195872.07
     * last_accessed: 1164196137.86
     * timeout: 3600

i'm developing an application who uses Session for store user data after 
users logins correctly,

I use in every request after login:
ses = Session.Session(req, timeout = out)
This Session object is what i show you at mail head.

Session stores correctly all data and detects is_new ok, BUT, session 
expires in (created + timeout) time, NOT in (last_accessed + timeout) 
time. Last_accessed as you can see, changes correctly, but after timeout 
(3600s. - 1 Hr.) using the application, session is deleted an users must 
login again.

How can i correct this?

Regards.
Rubén

P.D. Using Debian Sarge Mod_python version: 3.1.3-3