[pstricks] PSMatrix and Node labels

[Thomas Mensink]

Hi!

I have a PSMatrix with two kinds of nodes, circles (with text inside)
and gray squares, and there are some arrows.
This is easy using the psmatrix environment

eg:
\renewcommand{\PN}[2]{[name=#1,mnode=oval,linewidth=0.1mm]{\ensuremath{#2}}}
\renewcommand{\FN}[1]{[name=#1,mnode=f,fillstyle=solid,fillcolor=lightgray]}
\begin{psmatrix}
	\PN{pn1}{1} & & \FN{fna}&
	\PN{pn2}{2} & & \FN{fnb}&
	\PN{pn3}{3} & & \FN{fnc}&
	\PN{pn4}{4}\\
%draw some lines
\psset{shortput=nab,labelsep=3pt}
	\ncline{pn1}{fna}
	\ncline{fna}{pn2}
	\ncline{pn2}{fnb}
	\ncline{fnb}{pn3}
	\ncline{pn3}{fnc}
	\ncline{fnc}{pn4}
\end{psmatrix}

However, I want to add a label below (or above) the squares denoting
what the mean (eg the label f_1)

But I can't figure out how to do that. I have tried to use nput and
uput, but they just seem to display nothing.
Has anyone an idea?

Thomas