Thanks, comtrjl, this finally did it! Though I still had try try a lot ...
The article for Word 2002 (which has a different system menu) can be found at
http://support.microsoft.com/kb/319719/de.
Now, the problem ist: The Read in-addin is activated by default, but still not shown. So I have to deactivate it first, close the submenu, open it again, activate it, then it is shown.
Not the best of all solutions, but still quite better than opening Outlook all the time and now being able to print pdf as well ...
Bricks and stones won't hurt my
Word, and glue and tape hold it together ...