Transparent scrollpane background

I everybody,

I have a problem with the background of my customize scrollpane. By default, the background is white and I can’t made it transparent… I can change the color

_global.styles.ScrollPane.setStyle(“backgroundColor”, “0x000000”);
but the only way I find to made it transparent is to set the alpha to 0.

It will be a good solution if the movieclip I attach on the scrollpane doesnt have a rollover…
In fact, the alpha = 0 made disappear the rollover.

I try many thing, but all doesnt work

_global.styles.ScrollPane.setStyle(“borderStyle”, “none”);
_global.styles.ScrollPane.backgroundColor = null;
_global.styles.ScrollSelectList.backgroundColor = undefined;
mc_scrollpane.setStyle(“backgroundColor”, “transparent”);
mc_scrollpane.boundingBox_mc.backgroundColor = undefined;
mc_scrollpane.boundingBox_mc._visible = false;
etc…

Please, help me to find a solution !

Tks all