Este es un simple ejemplo sobre como crear una scrollbar via actionscript.
PLAIN TEXT
Actionscript:

import fl.controls.*;

import fl.events.*;

import flash.display.*

// CREATE CONTAINER - the scrollable obj

var container:Sprite = new Sprite();

container.x = 100;

container.y = 100;

container.graphics.beginFill(0xFFCC00);

container.graphics.drawRoundRect(0, 0, 200, 400, 0);

container.graphics.endFill();

addChild(container);

// CREATE SCROLLBAR - the scroller

var scrollbar:ScrollBar = new ScrollBar();

scrollbar.direction = ScrollBarDirection.VERTICAL;

scrollbar.move(container.x + container.width, container.y);

scrollbar.setSize(scrollbar.width, container.height/2);

scrollbar.setScrollProperties (scrollbar.height,0,container.height) ;

addChild(scrollbar);

// SETUP LISTENER

scrollbar.addEventListener(ScrollEvent.SCROLL ,onScroll);

function onScroll(event:ScrollEvent){

trace("scrolling [...]