sessions, cookies and rails 3

Hi *, my question is very simple, I must be going crazy for not being able to do something like this ...
I've tried setting cookies with cookies.permanent[ :foo ] (both string and symbol) and reading it after a redirect, but both cookies and cookies.permanent are empty. I then tried in the old way, using :value and :expires ala rack, no luck. Considering it was superweird I've tried with sessions, and using session[ :foo ] has the same result, everything is empty.
I've tried basically everything, changing string to symbols, inspecting everything, even switching from 1.8.7 to 1.9.2, cookies and sessions are not set, no matter what.
Am I missing something obvious here ? Some kind of configuration maybe ? I have the pragprog book but they barely mention cookies, only for storing sessions (btw, wtf?).
Your help is very appreciated, I'm lost.