Problems while translating into German

Hello @all...

I'm about to translate the membership-plugin into German. No major problems, except one:

I tried to translate the message "Completed: Thank you for signing up. Your subscription to our site is now set up and you should be able to visit the members only content."

I found this text in membershipincludes/plugins/gateway.freesubscriptions.php - and I replaced the English text by a corresponding German message. Then I uploaded the file to my server.

After that I went through the registration process (I tried it three times). But nothing has changed. The English version is still there, not replaced by the new German text.

I don't see why. Where's the mistake I have made?

Thanx for your replies.