Localization problem in nested-attributes validation


I recently run into a problem with the new feature for activerecord:
nested attributes. When the nested object (Activist) is invalid, the
error messages are shown, but the object name is noch translated. (My
project is in german)
So I get int the error box:

"Bitte überprüfen Sie die folgenden Felder:

    * Activist surename muss ausgefüllt werden
    * Activist city muss ausgefüllt werden"

In my appropriate localization file (de.yml) I defined the object/
attributes names correctly.

      protest_mail: Protestmail
      activist: Aktivistin
        body: Inhalt
        surename: Nachname
        city: Stadt

The error messages for protest_mail are transalated correctly, so I
guess, the problems applies to the new nested-attributes feature.

Any idea how to fix this?

best regards,