Installing one will lead to repeated code P111E Coolant Temp Not Plausible. The ECM compares various temp sensors at cold start and if one is different than the others (your coolant temp would be higher than the others) it throws the code.
If you call Webasto Tech they will not recommend installing. There is no work around.....yet.
Also, if you try to install one DON'T tie into the factory fuel lines, they are under 60 to 90 psi of pressure and will immediately flood the heater with uncontrolled fuel.