Attaching Main Camera to a livestreamed avatar from Xsens

Hi! I am developing a multiplayer VR game in Unity. I am streaming live body motion from the MVN Analyze into Unity, and this works fine. My problem is when I want to mount the Main Camera in my XRRig into the MVN avatar's head. I want to create a setup which is similar to this YouTube video : https://www.xsens.com/news/lets-go-full-immersive-vr - except that I dont stream finger data, and use the HTC controllers instead.

We are using HTC Vive headset and controllers, as well as the MVN Awinda body motion capture sensors. I have tried to set the Main Camera as a child to the Avatar and its head in many different ways, and it seems to spawn far away from the head in play-mode even though I place it correctly on beforehand. I've also tried to make a transform script which should transform the main camera's position and rotation. Any advice on how to tackle this?

Best regards