Tracking a third motion controller Via C++ or Blueprints?

Hello, I was wondering if anyone knew of any way I could use a third controller to record a mixed reality trailer? I checked out this video on stormy studio and this is exactly what I want to try and do in unreal. I already have a green screen space, and camera’s to boot, as well as a USB cable and a third controller. What I want to know is how to get this working in Unreal 4? I was looking around and there’s supposed to be mixed reality support for UE4, but I can’t find any tutorials on it myself. There have been whispers of it being possible in C++ But I’m not certain. I am not a programmer, but someone I will be working with on Monday who has some experience working with Unreal’s C++ compiler and the whole Uobject architecture. If anyone could point me in the right direction or provide some insight onto how to do this? I want to attach a camera to the third controller. I have managed to get it tracking in the Steam VR by plugging it directly into the computer, but there’s no way for the engine to handle a third controller? I only have access to one Vive so any help would be greatly appreciated.

Only for SteamVR. If a third controller is mounted as a Vive Tracker, select ‘Tracker’ device type in the first node.

So how would I “Mount” a vive controller as a tracker? Would i have to change what it’s idenitifed as in the C++ class? Or would i just get the array index of 2 for the device type of tracker then that will work as it IS the third tracked device?

Update: So we managed to get an object tracking to the third controller, we create a a free cam Init, that updates if a third controller is detected that can be ran on a construction script or play. As well as the actual tracking of the object. I am currently looking at how to project the camera to the “Play from VR” Viewport on the desktop monitor so I can use recording software to record the screen and will update once I have figured how to set the camera to be Desktop viewport camera.

There was the utility from HTC to make SteamVR think that Vive Tracker is a motion controller. I think it possibly can do on the contrary.