Java SE (Java Platform, Standard Edition)

Hi all,
I'm trying to create a tristate checkbox. I want to change the displayed image on the third state, so the three states would be something like this:
http://nawad980.spymac.com/images/java/BlankCheck.gif Blank (First State)
http://nawad980.spymac.com/images/java/YesCheck.gif Yes (Second State)
http://nawad980.spymac.com/images/java/NoCheck.gif No (Third State)

I've seen many posts that use the setArmed, setPressed and setSelected methods of the ButtonModel, but that's not what I want. I need to change the painted image on the checkbox, but I can't seem to know where that's done.

Any Ideas?

P.S.: I'm sorry for the mess above, but the stupid editor of this forum is so limited, so I couldn't insert an image in my post. I hope they will improve it someday.

Best regards,