border of bars in lattice barchart

Hello!

How to change a color (or linewidth) of
border in lattice 'barchart'?

I am trying

barchart(
	(......) - my arguments
            panel=function(x,y,color,subscripts,groups,...)
            {
panel.barchart(x=x,y=y,box.ratio=2,col=color,border=FALSE)
            }))

or
...
panel.barchart(x=x,y=y,box.ratio=2,col=color,border='transparent')
...
or
panel.barchart(x=x,y=y,box.ratio=2,col=color,border='red')

but it has no effect.

is there any other way to change a barchart border?