how do you diagonally scroll?

hi
i have made a custom scroll bar
however when i change the angle of the scrollbar and the scroll line ( they are on the stage) it continues to scroll verticaly
please help me out!

here is my function and bounds box;
var bounds1 : Rectangle = new Rectangle ( Box2_mc.ScrollLine_mc.x , Box2_mc.ScrollLine_mc.y, 0, 170 );

function enterHandler ( myevent : Event ) :void{
if ( scrolling == true ){
Box2_mc.TextFieldSnook_Txt.scrollV = Math.round( ( (Box2_mc.scroll1_mc.y - bounds1.y)/170)*Box2_mc.TextFieldSnook_Txt.maxScrollV);

}
thanks
matt