Lewm
The easiest solution I can see to your problem is to have the switch control a relay. If you have lowish DC voltages available (preferably either 5V or 12V) this is easy to do.
You'll need some logic to convert the momentary action to a latching action but it's not hard to do. Since I have B+ delay on all my valve gear I use mains switching by relay as a matter of course anyway and I like the safety aspects.
Mark Kelly