Setting locale directories for I18n

Rails 3.1.3

I would like to apply i18n for my application.

Since there are many yml files in config/locales directory, I have made
subdirectories so that the maintenance will be easier. For example,

config/locales/devise/
                       date/
                       top/
                       ...

Each subdirectories contain corresponding locale files that are applied
when users change the language setting.

My question is:

How can I set the load_path for locales ?

in 'application.rb'

    config.i18n.load_path += Dir[Rails.root.join('config', 'locales',
'**', '*.{rb,yml}')]

seems to work if the language setting is NOT dynamical. But I need to
set
initializers/i18n.rb in order to change the languages dynamically.

I18n.default_locale = 'en'
LOCALES_DIRECTORY = ######HERE???

LANGUAGES = {
  'English' => 'en',
  'Français' => 'fr',
  '日本語' => 'ja',
  'Deutsch' => 'de',
  'Español' => 'es',
  '한국어' => 'ko',
  'Русский' => 'ru'

}

so hopefully, application_controller.rb can call the directories.

How should I set "LOCALES_DIRECTORY" ?

soichi