First thing I would do is call Lumina and ask them for help, your issue can't be unique and they may have a solution for you. If they can't help then maybe shielding the cable from the battery to the headlamp will help, also a simple pi filter (inductor/capacitor) on the input to the headlamp can be a solution. If the issue can't be addressed with a power filter you're screwed. In that case, the PWM power converter inside the headlamp is radiating and the PWM needs to be tweeked to make it stop interfering with your computer.