(Flash + GoogleMaps) How to custom zoom and span controls?

I’m building an application using flash and google maps. Now I’d like to customize the zoom and span controls. I found a similar solution on http://visitsweden.com/sweden/Regions--Cities/Stockholm/ , but unfortunately I don’t know how they built it. I guess they have used images to custom the controls.

So, if anyone knows how to custom the controls with images, please let me know. I’d be more than grateful.