Here are some screenshots of my problem.
I created a cube as an avatar (it will be replace by the hands).
Then I created a DefaultAvatarTransform and set it to the fphandler:
Cube cube = new Cube(1f);
this.avatar = new DefaultAvatarTransform( cube, 0, 0, -1, getRootBG() );
getFpHandler().addAvatar( avatar );
The avatar has a [0,0,-1] offset so I can see it.
When I turn the camera to the left, the avatar stays to the right.
The same when I move the camera up and down. The avatar seems to go to the opposite direction of the camera.
Look at the screenshots.