I have also heard of guys using an empty .22 shell casing over the pin to make it reach. Alternately you could just get a new pin and spring from Toyota.
There are 3 small screws behind the steering wheel that take the cover off the face of the steering wheel, the surround for the horn buttons, then you could see the wires that go from button to the contact pin. MANY, MANY, MANY fj60 have had...