To_json in Rails 2.0.2 not generating proper json?

Rails
1

I am using Rails 2.0.2 and trying to use to_json to generate json. I
notice several problems.

  1. datetime field such as created_at mapped to “created_at”: {}
  2. :except does not work, @post.to_json(:except =>
    [:created_at, :updated_at] still gives me “created_at”: {},
    “update_at”: {}
  3. problem with escaped char mapping: ‘<’ mapped to ‘\074’ instead of
    ‘\u003C’

Is there problem with my installation? Is there a module I should turn
on?
Do I need jsonifier plugin?

Help please!
victor