The A340 arrived from AKl with 10 t of motion lotion on board. they put another 115 t ish and the wing tank fuel temp stabalised at around 10 c The outside air temp was +3 c and they had what appeared to be ice behind the rear spar, ie where the fuel could not warm the wing. How you get ice in these conditions I am not sure but I do know that no one, Eng or driver got up on the wing and had a feel. Suspect they had a layer of frost and a simple sweep with a broom would have sorted it.