[Za4a Tuner]

Hello;
i've got a question to the "form_output_styling".

How can i use the "<vb:if>"-conditional for questions like grid or radio-button?
I'd like to have it that the question and answer is only shown, when the user answerd the question.
I tried:

<vb:if condition="$q[13]">{qn_13}[list]{q_13}[/list]<vb:else /></vb:if>

But this does'nt work, the question and answer is allways shown
How can i get my form to show only answerd questions?

kr Chris