Adding mounts in Titan Quest - advice needed

Hello, for some time now I have this idea to make a mod for Titan Quest, where you can buy and “equip” riding animals. Many creatures in the game can become mounts as long as there is a proper animation for the rider and the animal. An example of horse rider:

For now I manage to combine the animations, however it would be great if the mounts can be bought separately without always being attached to the character mesh. I can think of one way to make it possible, but it requires two things that I don’t know how to do.

  1. I have to add a new weapon class to the game (the actual mount), which is linked to the new set of animations. No idea how to do this.
  2. I have to make this mount-weapon to equip exactly as armor. Again I don’t know how to do it.
    Here is another video, showing the main idea:

Or maybe there is a better way? I hope someone here can answer my questions or give me advice.