Dear Klas,
thank you for your reply. Your suggestion to use a Free Text field worked. Because there is an issue with the JCE-Editor (Changes are not saved if I am in code view, I always have to switch back to the "editor view" before saving), I would prefer adding the html to the template itself as you suggested. But I don't know where to do so. All code added to index.php will be rendered after the form, but I want it right before it.
btw: I was able to change the markup of the headline to h1 by changing the menu item option "show title" to "show". Now I can select the level of the heading manually.
Sven