Flash :: Implement A Infinite List In Flex (hero)?

I'm new to Flex/ActionScript (.NET/Java has been my main playground so far).I'm trying to build a Flex app that has a list that is meant to look and behave like an infinite list (of items - which can be any object). The idea is that the user should be able to scroll up or down and never reach the end of the list in either direction.

An example would be a list of numbers. Scrolling up will show negative numbers; scrolling down will show positive ones. Now, my list is a simple Flex Spark list (using Flex Hero).It is bound to a data provider that is an ArrayList.My initial idea was to listen to the scroll event and add/remove items as needed. However, in the current build of Flex Hero, there is a bug that doesn't raise scroll events for vertical scrollbars sometimes (http:url].....).So, I'm using the workaround suggested in the link above (i.e listening to the propertyChanged event of the list's scroller's viewport. The event though only gives me the current verticalScrollPosition. And it looks like the default spark list supports smooth scrolling and raises the event many times before the list scrolling comes to a standstill (it is a nice visual effect).Now, I need to :

Figure out whether it is scrolling up or down (how do I do that?)

Figure out which items are visible. I can get this from:

list.dataGroup.getItemIndicesInView()

Add/remove items as needed, so that the user can scroll up and down forever, never reaching the end of the list in either direction.

I've tried the following code but it doesn't work. (comments in code).

import mx.collections.ArrayList;
import mx.core.INavigatorContent;
import mx.events.FlexEvent;[code].....