Make clicking on the button toggle a Boolean.
Check for the Boolean, if enabled, set the object invisible.
Else, set the object visible.
<img src="smileys/smiley4.gif" border="0" align="middle" />
If you want to save events in the free version..
Make two buttons, create one over the other, make the top one invisible by default.
When you press the bottom button, it sets the top button to be visible and also makes the other object invisible.
Pressing the top button would hide itself and make the other object visible.