ActionScript 3.0 :: Goto URL On Button Click, With Parameters

I am trying to make a series of images act like buttons, where each button opens a new browser window with a url of my decision. I have put in the images, converted them to symbols (buttons) and given them an instance name.

Now, the AS3. The following works for me:

Code:
btn_bent.addEventListener(MouseEvent.CLICK, buttonClickHandler_beton);
function buttonClickHandler_beton(Event:MouseEvent):void {
navigateToURL(new URLRequest("http://www.hattingks.dk/Default.aspx?ID=6587&ProductID=9866200&VariantID=&GroupID=vogne"));
}

But I wouldn't want to make a new function for each button. I have tried to extend the function to take two parameters like:

Code:
buttonClickHandler_beton(Event:MouseEvent, www:String):void