Controlling flex chart axes

|       |        |
9:46    10:46    11:46

[Bindable]
  private var expenses2:ArrayCollection=new ArrayCollection(); // computed elsewhere
  private var labels:ArrayCollection=new ArrayCollection( [
           { Time: "10:38"},
           { Time: "11:08"},
           { Time: "11:38"},
    		 ]);
...
<mx:LineChart  dataProvider="{expenses2}"  ...>
        <mx:backgroundElements>... </mx:backgroundElements>
        <mx:horizontalAxis>
           <mx:CategoryAxis
                dataProvider="{labels}"
                categoryField="Time"
           />