You're using the VolumeManipulator. This camera is for manipulating volume, this is the camera used in the viewer tool and some tutorial. The pivot is at the volume center, not at the viewer position.
You may wish to try instead the FreeCamera from the gamekit package, which possibly seem to do what you need.
The gamekit demo uses it in CameraMover (also used in the editor tool) and also shows how to sync the camera position with another object. The script moves a GameObject, but you can do same with a model if you need to.