Devise & manual password change


i'm trying to use devise gem 1.1.1 on a new rails 3 app,

I would like to change the password of my users from the console,
user.password= works well in dev, but in production, despite the
encrypted password has changed, i can't log in the application.
(user.reset_password!(new_pass,new_pass) doesn't work neither...)

Would apreciate ...