Dear Robin,
thanks for coming up with a solution but this is not working for me. Because of two reasons, if I create a page for every forum (and subforum I am using), I don’t have real forum overview anymore.
The second reason is, I am using BuddyPress, where people can create facebook like groups. Those groups will get there own forum, which won’t appear on the site if I do it this way.
So it looks like I have to do some tweaks to the code that adds topic title to the output. Honestly it’s really weird that bbPress is behaving like this. I’ve never seen a forum that doesn’t show a titles on the front page.