Sure, you could do something like this:
<mx:Script>
<![CDATA[
import mx.controls.Alert;
private function btn_click(event:MouseEvent):void
{
Alert.show("Clicked!");
}
private function btn_keyDown(event:KeyboardEvent):void
{
if (event.keyCode == Keyboard.ENTER)
btn.dispatchEvent(new MouseEvent(MouseEvent.CLICK));
}
]]>
</mx:Script>
<mx:Button id="btn" label="Click Me" click="btn_click(event)" keyDown="btn_keyDown(event)" />
... although I'm not a huge fan of dispatching events on objects outside of those objects. A cleaner approach might be to subclass Button, add the listeners and handlers inside your subclass, and then dispatch the click event from within that class. But this should help illustrate the point. Good luck!