Jon, I had found those too, left hand side looks the best option. I had read on ih8mud that a US army guy had a look at them out in Iraq. He suggested that the 105 shell had captive nuts on the inside ready for them. I am not sure the 100 series has the same nuts. The bottom 2 steps could have reinforcement plates like you did for your tyre swing out, but I am not sure the top one would be so easy.
On a different matter what tyre swing out parts are you after? I still haven't put mine on