Just did mine this week - two wires broke and the bike died (fortunately just as I got home) and the unit needed replacing. I could have bodged the wires together but I reckon this is a pretty fundamental bit of the electronics and I don't want it to fail again. Switch here in Ireland was €70 plus €0.50 for the screw (which I didn't need!). Scrape off the red stuff and a small jeweler's screwdriver will do the job. I found that I did not need to unscrew it completely to get the switch to drop out and the new one slotted in quite easily.
Cheers,
Psyko