Here are a trio of pictures that make it more clearly.
Yes I heated up a drill bit and made the holes as the plastic is brittle and hard. One thing I would do differently is to use a size smaller wire.
Note in the picture that follows that the wire is bent upwars in a triangular fashion away from the bottom of the button. This is crucial as it resembles the actual bit that breaks away and it helps to clear the cogs when the button is not pressed in. Do not leave it in a square shape but pinch it with pliers so it looks like this. That is why a thinner wire would be handy and more appropriate.

Here is a picture with the button standing and one in the assembly.

and the last one

It is not the prettiest of jobs but it works.
Yes, I am in the lookout for a 3D printer but I believe for this we would need pictures of an unbroken button so we could copy it. If I only had a 3D printer (that is my Xmas Wish for next year though)
If anyone is willing to 3D print these then I am in the line to buy some