Make a Rock Band Drum Pedal Pad

Step 4 Test it.

Google "Rock Band Drum Machine" and install the nice software Andrew Rudson made (free) to test the new pad.  Unplug the kick petal and plug the keypad in.  Check and make sure it works before you put it all back together.  You should be able to just line up the layers and use your finger to complete the circuit. 

Unplug it from the kit before you solder.  There is no power going through the switches so you should not damage anything.  But try it at your own risk.  If it satisfactorily works (at least a few keys close together)... hot glue any exposed wires, and hot glue where the wire comes out the side to make sure you can't pull it free.