Colorbar too wide in eps

Hi!
When I plot my filled.contour plot

filled.contour(dat,color=rainbow,plot.axes=matrix.axes(dat),xlab=myxlab,ylab=myylab)

everything looks fine on the screen.

But if I wrap these two lines

postscript(file="myplot.eps",paper="special",width=4,height=4,family='Times',horizontal=FALSE)

...

dev.off()

around the line above in order to create an eps file, the bar is much too wide.

I tried to play around the "witdh" parameter of the "postscript"
command and tried to use the "legend.width" parameter on the
"filled.contour" command - without success.

Anybody ran into a similar problem once?

Thanks for helping me out,
Max