replacment apple joystick button switches

[Hatta <hatta@softhome.net>]

I picked up an Apple II joystick, model A2M2002. 
The joystick works just fine, but the buttons
don't work.  

I can open up the joystick, and bridge
the connections and peek at the buttons 
and see them work. So I know the connection
is ok. 

When I press the buttons they click, so the
switches ought to be engaging. So I'm pretty
sure the switches are bad. They say "omron b3f"
on the back of them.  But there appear to be
many different types of these.  Does anyone
know what switches I can get to replace these?
Thanks
-Hatta