It looks like it's just riveted in there, I would get see if you can replicate the shape of the holder with some metal, not sure the gauge, if you have a micrometer (or harbor freight has this in/metric one that I use for small stuff) take some measurements. Looks like a little fold + some snips to make the arm. A small file (triangle?) for the notch that grips the rocker. If you cut out the center portion of it to make the arms, consider cutting strips, then prying back and forth for a clean break. If you can do all that, consider drilling the rivet out, then placing a new one in. Now my question would be does it matter about the copper rivet. I wanna say no, but I'm not a scientist. U can do it!