try this
Working in Special Effects, I have had great success in iginting Pyrotechnics using a single strand of a multi conductor lamp cord. Sinply cut a chunk of a lamp style cord, and use one of the many fine coper wires that make up the one larger conductor, wrapping it around the fuse, close to the body of the Pyro. Then connect the two ends to a heavier piece of wire. I can get ignition on this with a 1.5v AA battery, so I cant imagine it not igniting with 100v.
Your other option is to ignore the generator within the plunger, and adapt a microswitch that triggers a battery hidden in the unit, every time the plunger is depressed. You will still get the really cool "look" of using a old-fashioned plunger, but will get a good, solid ignition voltage from it.