+1 indeed! I'd been thinking of doing this since my last couple of episodes of taking my A419s apart - seemed like quite a hassle.
How did you do this mod on the board inside? Did you simply remove the original switches and add leads to extend them to the outside world? Any warnings or tips?
A jumper is nothing more than a manual switch; when you put the jumper on two pins it shorts the two pins together. When you put the jumper on just one pin you open the connection between those two pins. Really when the jumper is on one pin that is just a convenient place to store the jumper. It is doing nothing electrically at that time.
On the inside I took off the jumpers and wired each pin on the jumper header to a pin on the switch. It was quite simple.
You need a single pole single throw (SPST) switch, aka a on/off switch. There are many options; toggle switch, rocker switch, slide switch. My switch was a TS02CBE from digikey. If I had to do it again I would have bought a right angle switch because I had to bend the pins on the switch to close the A419. http://www.digikey.com/product-detail/en/TS02CBE/CKN9924-ND/2055202
I used female female jumper wires to wire from the switch pin to the jumper pins on the A419. These are really easy to use. You just push them on pins. You can google for these.