lattice plot problem!

Hello everybody,
	Could I consult you two questions?
	Recently I write some code about lattice plot.
1) bwplot function
	I know the lattice default background color is grey and the box color is green, but I don't like the color. So I change the background color to white use the

trellis.device(bg="white") 

then I modify the

panel=function(...)

+{
+	panel.bwplot(col="black"...)
+	}
	
	But I find the the box color is still green, just change the color of point which is in the box, I guss it is the mean or median value of the data. So How to change the color of box, and how to change the shape of the point in the box. I want it like other boxplot, like a horizontal line.

2) In every lattices, I want to add a mean line of the group. I try the

panel.abline(h)  

But I find in very lattice add the same line. Then I try the "panel.linejoin" etc. But I can not get my wish plot.

	Could anyone help me to settle these problems?
	Thanks very much!

Best Regards!
Ivy Li£¨Àîè¡£©
YMS in Production & Testing
Semiconductor Manufactory International(ShangHai) Corporation
#18 ZhangJiang Road, PuDong New Area, Shanghai, China
Tel: 021-5080-2000 *11754
Email: Ivy_Li at smics.com