[TYPO3] Translate: email address not valid

[Bas van der Togt]

Hello list,

Does anybody knows how to translate the error message (Email address not 
valid) when i let typo3 do a email check on the frontend?

So don't mean this:
tt_content.mailform.20.badMess = Please fill in the following fields:
tt_content.mailform.20.goodMess = Thank you!

cheers,
Bas