Garden Gnome Software

I'm looking to put a "sound on" and a "sound off" button on my controller. On the silhouette skin the mode button is toggled depending on the mode selected. Initially I was going to have the off button next to the on button but having them toggle makes more sense. Looking at the skin there doesn't seem to be anything obvious as to how this is done as placing them on top of each other doesn't work.

Any pointers please?