[NTG-context] vertically centred

[Peter Münster]

Hello,
how could I centre vertically a table or a vbox?
In other words, how to do the same as the following LaTeX code in ConTeXt?

\documentclass{article}
\begin{document}
a box with a table:
\fbox{\begin{tabular}[c]{l}1\\2\\3\end{tabular}}\par
a mid-aligned parbox: \parbox[c]{1em}{1 2 3}
\end{document}

I tried with \vbox to 0pt{\vss ... \vss}, but then the vertical dimension
gets lost...

A related question: where are the differences between
\framed[align=low,high,lohi]{...} ?

TIA for any help, Peter

-- 
http://pmrb.free.fr/contact/
_____________________________________
FilmSearch engine: http://f-s.sf.net/