How do I create custom dominoes in Table Top Simulator?

How Dominoes are Different From Other Pieces

In the game, there are domino objects. The main difference (mechanically) between dominoes and other objects is in their vertical rotation snap: when a domino is picked up off of the table, it will snap to being upright, as well as the standard face up and face down. Other types of objects have different snapping rules; custom models only snap face up or face down, figurines only snap face up, and dice have no snapping.

The Problem

I have already verified that there is no way to spawn a custom object with domino-like snapping using an in-game menu. However, I can't seem to find a way to create such objects by editing the save files or the like either.

I am trying to make a set of Icehouse pieces. While there is currently an icehouse set in the workshop, that set no longer works as many of its resources no longer exist.

What I Have Tried So Far

The current icehouse pieces I have look like this:

{
  "ObjectStates": [
    {
      "Name": "Custom_Model",
      "Transform": {
        "posX": 0,
        "posY": 0,
        "posZ": 0,
        "rotX": 0,
        "rotY": 0,
        "rotZ": 0,
        "scaleX": 0.875,
        "scaleY": 0.875,
        "scaleZ": 0.875
      },
      "Nickname": "3",
      "Description": "3-Pip Icehouse Piece",
      "ColorDiffuse": {
        "r": 1,
        "g": 1,
        "b": 1
      },
      "Grid": true,
      "Locked": false,
      "CustomMesh": {
        "MeshURL": "http://pastebin.com/raw.php?i=8AjNn4j9",
        "DiffuseURL": "",
        "NormalURL": "",
        "ColliderURL": "http://pastebin.com/raw.php?i=8AjNn4j9",
        "Convex": true,
        "MaterialIndex": 0,
        "TypeIndex": 0
      }
    }
  ]
}

I have tried manually changing the TypeIndex (corresponds to object type), but any value larger than 5 causes the object to fail to load, as the type index only goes up to 5.

I also tried changing the Name field. Changing it to "Domino" (which is the value found on domino objects) does give it the desired vertical snapping, but it replaces the model with the game's double-zero domino (the domino's model depends on the MeshIndex field, which defaults to 0).

How can I create objects with custom models that have domino-like vertical snapping?