What about adding a dollop of methanol, or even ethylene glycol to the mix? It could be that the freezing of the water is what is triggering the separation of the kerosene and oil. Something that would act as an antifreeze to the water just might extend the temperature downwards enough for us to fly in sub freezing weather.

If it does not act as an antifreeze in the conventional sense, the hygroscopic nature of methanol might help it bond with the water molecules and again prevent the kero and oil components from separating. I'm just guessing, but it sounds worth a try. Methanol would be my first choice.

Ed Cregger