After googling some time around, I found the solution to translate the Caroline theme. For the next time (and also for others having the same problem), here a short HowTo.
First of all, there are a lot of translations available, also for Coraline: http://translate.wordpress.com/projects/wpcom/themes/coraline/ and if there is nothing for your language it would be great if you do you translation here to help comunity.