[Plugin: Contact Form 7] acceptance_as_validation: on not working?!?

Hi,

I seem to have the same problem as this guy here.

Maybe I’m doing it wrong, but when I enter acceptance_as_validation: on in the additional settings the form stops working all together. I need to show a message when people click on submit and the acceptance box has not been checked. The Submitbutton is styled differently so they do not even see that it is disabled… ??

Thanks for your help

Sascha