I'm trying to accomplish the same thing illustrated in this post: http://stackoverflow.com/questions/4132392/how-can-i-create-a-flex-list-component-with-the -0-rowindex-starting-at-the-bottom
I'm almost there, I'm just having trouble with the scrollbar because it's still top-down. In the demo, you can see only the first 4 of 10 items are visible and the scrollbar moves in the wrong direction.
Right-click to View Source.
It's almost easier to do something like this than try to figure out code in VerticalLayout
Again, right-click to view source.
You might find it useful to work through the exmaple in this blog post:
It's a simple horizontal layout example, but if you make three small changes you can get the order of the elements to be reversed. Change these lines to be...
Line 304: for (var k:int = target.numElements-1; k >=0; k--)
Line 254: var element:ILayoutElement = target.getVirtualElementAt(target.numElements - 1 - k);
Line 169: for (var i:int = layoutTarget.numElements-1; i >=0; i--)