PrintJob.addPage(...);

I’m trying to print an object (currently a MovieClip) from the stage or library in Flash CS3 using AS3. This is my code so far:

var myPrintJob:PrintJob = new PrintJob();

function PrintMyPage() {
    myPrintJob.start();
    myPrintJob.addPage(printObj);
    myPrintJob.send();
}

function printCLICK(event:Event = null):void {
    PrintMyPage();
}

printBut.addEventListener(MouseEvent.CLICK, printCLICK, false, 0, true);

Where printObj is my MovieClip I want to print. I’ve also tried exporting the printObj MC for AS and changing its base class to a Sprite with a class of ‘printObj’.

What am I doing wrong? How can I get a MC to print using the addPage(); method?