I also have been trying to get this to work, though I am not sure if I'm using it for the right purpose. I am looking for a way to change my czmldatasource's billboard image icon if I zoom out too far. And I want to change the image back to it's original icon when zoom within good range. I need this function mainly because I have lots of objects on the globe.
If anyone knows how to use this and can show me an example, I'd greatly appreciate it! Thanks!