I finally got a reply from the OEM, installation with the standard HUF barrel, not the OE, is very simple.
1. Fit the inner valve barrel into the sensor, loosely.
2. Install into the wheel finger tight only, at this point the sensor should be lose on the wheel
3. Pressing the sensor body flat against the inside of the wheel torque down the outer barrel to 4Nm. This must be done with a torque wrench.
4. If during the torque down process you may feel a sensation similar to that of stripping the thread, this is normal. Continue to tighten the outer valve barrel to 4nm, you may need to finger tighten the barrel again if the rim is very thin walled.
Note: if step 4 occurs then the outer barrel should be replaced every time the sensor is removed from the wheel.
The BMW OE barrels are designed to work with BMW OE wheels & may not work with aftermarket wheels.