Can't translate the messages of the flag module I'm using Drupal 7.20 with Commerce. I installed the following modules:
 - internationalization module
 - translation helper
 - flag module

I have customized the text for my flag links to be 'add to my favorites' and 'remove from favorites'. I want to translate them, but they don't appear in the translate interface.

Does anyone have a clue?
See this from the Flag module issue queue


  Each string you enter as an administrator is available in the Translate Interface section, but you first have to switch to a different language, then view a page that contains that message (such as trying to flag/unflag a piece of content). Afterwards, the string will be flagged as needing a translation and you can find it in the Translate Interface section.