Changing color of points in violin plot

Hello,

I am trying to graph a violin plot like the example in 
panel.violin(lattice) with the singer data - see below

Does anyone know how to change the color of the boxplot on the graph 
from blue to green?  I tried a number of changes, but to no avail.

Thanks for your help,
John



bwplot(voice.part ~ height, singer,
            panel = function(..., box.ratio) {
                    panel.violin(..., col = "transparent",
                                      varwidth = FALSE, box.ratio = 
box.ratio)
                    panel.bwplot(..., fill = NULL, box.ratio = .1)
             } )