You'll have to manually create an instance of the State class and create overrides for it. Then add the newly created state to the states array of your component.
Here's a small example air application that shows how to do it:
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx">
<fx:Script>
<![CDATA[
import mx.events.FlexEvent;
import mx.states.AddChild;
import mx.states.AddItems;
import mx.states.SetProperty;
import mx.states.State;
protected function createState(event:MouseEvent):void
{
var label:Label = new Label();
label.text = "World!";
var addLabel:AddItems = new AddItems();
addLabel.relativeTo = foo;
addLabel.position = "after";
addLabel.items = label;
var helloWorld:State = new State();
helloWorld.name = "helloWorld";
helloWorld.overrides = [addLabel];
states = [helloWorld];
currentState = "helloWorld";
}
]]>
</fx:Script>
<s:layout>
<s:VerticalLayout />
</s:layout>
<s:Label id="foo" text="Hello" />
<s:Button label="Create new state" click="createState(event)" />
</s:WindowedApplication>