[TYPO3] Fe_users Front End User Registration does not work with direct_mail categories

[Johannes Konert]

Hi mates,
I am eager to find out, why I cannot use the same feuser-data for
direct_mail newsletters and the fe_users Front End Users.

I have a sysfolder with my frontend-users and a sysfolder with
directmail.
The frontend user registration works fine and puts the new users in the
right feusers folder, but the subscription form does not display the
direct mail categories. It only says in the form presented to the
website user (german):
"Möchten Sie News zu folgenden Themen erhalten? passthrough:nicht
unterstützt"

The list archive and google doesn'T help on passthrough with fe_users.
How can I make the categories appear and make it configurable for
feusers which newsletters they wanna have?

Thanks for your help.
Cheers
Johannes