[Typo3] mailformplus template parsing

[Dennis Heeren]

Hello all,
 I have a problem that's driving me crazy...
 I run T3 3.7.0RC2 and have the extention Mailformplus installed (v 3.6.1).
 Added a form to a page. All works well, I can submit the form, recieve the 
emails sent by the form and so on. But, there's a but, this only is the case 
when I'm logged in into BE.
 When I'm logged in to BE and preview the page where the form is on, 
everything behaves as it should. When I log out BE and just browse to the 
page, the form is not rendered. In the source of that page the code for the 
form is missing. Somehow it doesn't get parsed. 
 In the documentation of the extention I've found that I should check 
Startingpoint. I did: nok
I've been searching to the newsgroups and googled around the whole morning 
already and found some info that this could be caused due to 
cssstyled_content. I tried adding a piece of code to the setup.txt file in 
/public_html/typo3/ext/css_styled_content/static/ described here: 
http://www.typo3.net/forum/?&action=list_post&tid=3147 but also to no avail.
Also checked in my template resources that the CSS content was not there, 
but also didn't work.
Installed the css_styled_content, removed it, none of it works.
Clearing cache did neither work.
 Why oh why is my form not rendered when I'm not logged in in the BE? And 
how can I solve this?
 Any help is greatly appreciated!
 Dennis