It's easier to just solder the pin back on.
I've had several of these home button failures brought into my store and just put a slight dab of solder onto the connector from where it came. It's a very simply circuit and I've had 100% success with this method.
Make sure its bent up slightly to allow the pressure to connect onto the dock flex cable the activates the home button response.
Otherwise you have to fully disassemble the lcd, and heatgun remove the front panel/glass-digitizer and peal out the home button.