I don't know much about the situation, seems its working in other games from the "only LFS" comment, but I hope you will be patient as it worked for me in minutes... Have you tried the obvious things like restarting LFS, restarting the computer and the such? I don't know much trouble shooting advice here since I just plugged and played after a few settings in the profile thingy...
You could try reinstalling the TrackIR drivers. TrackIR works fine, for me, in LFS (although, regrettably, Patch Y has restricted its view to no more than 90deg. right and left, which makes it very difficult to drive in reverse).
To get full 6DOF support, within LFS, you will need to update the gaming application to version X.
To update to version X -
Start your current version of LFS (Demo or Full install).
Select the Multiplayer screen.
Click on List of Games.
You will then be given the option to automatically install the update; please allow.
The software will restart, providing full 6DOF support.
My version is the last test patch Y21.
But there is no problem anymore. I find out that it is necessary to mark "Axis" in the View option menu.
Now it works and the deep immersion is back. Not too easy to get used, but very fun for sure :-)