textflow removes empty spans

I create three unique spanelement's and put them into a paragraphelement in a textflow that's a textarea. The first and last span have text in them, but the middle on has no text as it's a placeholder that will have text set later on.

Flex then helpfully removes all the empty span's - even unique one's - including the placeholder.

Then later on I put text in the placeholder - which is no longer there. No text appears in the textbox and the placeholder doesn't return.

Does anyone have a solution for this? Any help would be much appreciated.

here's some code to demonstrate the issue:

<?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 flashx.textLayout.elements.DivElement;

import flashx.textLayout.elements.ParagraphElement;

import flashx.textLayout.elements.SpanElement;

import mx.controls.Alert;

import org.osmf.image.ImageElement;

import spark.utils.TextFlowUtil;

private var para:ParagraphElement = new ParagraphElement();

private var inc:int = 0;

private var span:SpanElement = new SpanElement;

private var span2:SpanElement = new SpanElement;

private var span3:SpanElement = new SpanElement;

protected function button1_clickHandler(event:MouseEvent):void

{

inc++;

span.id=inc.toString();

span.text="hello";

inc++;

span2.text = "";

span2.id=inc.toString();

inc++;

span3.id=inc.toString();

span3.text="hello2";

textArea.textFlow.replaceChildren(0,textArea.textFlow.numChildren,para);

para.addChild(span);

para.addChild(span2);

para.addChild(span3);

Alert.show(TextFlowUtil.export(textArea.textFlow));

}

protected function button2_clickHandler(event:MouseEvent):void

{

span.text = "changed";

span2.text = "dude where's my placeholder?";

Alert.show(TextFlowUtil.export(textArea.textFlow));

}

]]>

</fx:Script>

<fx:Declarations>

<!-- Place non-visual elements (e.g., services, value objects) here -->

</fx:Declarations>

<s:TextArea id="textArea" right="10" left="10" top="10" bottom="68"/>

<s:Button label="1) Create Text and Respond Immediately" bottom="39" click="button1_clickHandler(event)" horizontalCenter="0"/>

<s:Button label="2) Changed Placeholder and Respond" bottom="10" click="button2_clickHandler(event)" horizontalCenter="0"/>

</s:WindowedApplication>