Hi Daniel,
Email templates are mostly editable by template overriding the email template files. Make sure you are template overriding theme files so that your changes are protected from future updates. You can also do this in the backend so the override files can be created automatically(http://take.ms/SZSJ3).
If you are still having issues, perhaps you can provide us your site access so we can check this for you.

i have change this settings in post.new.php and template.php.
I also found these both files in templates/hausbauberater-de/html/com_easyblog/emails but it dont work!
Author, Logo, Heading, Subheading; Link for Author all Informations are displayed???

Hey Daniel,
We have found a bug. It looks like the file is being applied to the wrong override directory. There is a missing 'html' directory after .../emails/. The correct directory is as below.
JoomlaFolder/templates/currenttemplate/html/com_easyblog/emails/html/post.new.php
After you move the email override files here, the override should work.
I will log this issue in our tracker so it can be addressed.
Regards.