Here is what I'm stuck on.
I'm working on Symfony2 and trying to make the translations working. But somehow, I can't make it work as it should. Here's what I got.
In the config.yml

```
translator:      { fallback: de }
session:
        default_locale: en

```

In `messages.en.yml` I have this structure:

`Please log in: Bitte melden Sie sich an`

I also have similar files for `messages.en_US.yml`, `messages.ru.yml`, etc.

In the code I use `$this->get('session')->setLocale('ru_RU');` to change the locale.

But the translation works only when the locale is set to "en\_US" or "de\_DE". In any other case it returns the key, not the value. I try the translation with this code

`return new Response($this->get('translator')->trans('Please log in').' '.$this->get('session')->getLocale());` and it returns the locale I have set.

So what can cause this problem?