[NTG-context] matrices with horizontal and vertical delimeters

Hello, I have problems with typesetting of matrices with delimiters. I need the same functionality like in the following LaTeX example: \begin{displaymath} \left(\begin{array}{c|c} 1 & 2 \\ \hline 3 & 4 \end{array}\right) \end{displaymath} but in ConTeXt I can't find method how to do that. My best result is \startformula \startmathmatrix[left={\left(\,},right={\,\right)}] \NC 1 \NC \vl \NC 2 \NR \NC \hl \NC \vl \NC \hl \NR \NC 3 \NC \vl \NC 4 \NR \stopmathmatrix \stopformula But the result is not ok. In addition, I would prefer dashed lines. Thanks, Jiri Cigler