Setting up Center of Mass on Prop3d object without moving the object

Support
1

I am trying to set a centre of mass with SetOrientation() function and then apply RotationWXYZ() on the object. The thing is when I use SetOrientation on the object it moves it. I only want to set centre of mass around which to apply the rotation, not move it.

2

Does anyone know the solution to this? q.q