Engine PreHeater In The Plane

I am a member of a 3-way partnership in a Cessna 206. We have just
purchased a SureFire preheater. The source is available at:

http://www.crystal-airways.com/surestart/surefire.asp

It uses small camping style propane bottles which are readily available
at Wal-mart or other retailers. They do not actually fit in the
pre-heater storage box, so have to be carried separately.

We have belted the preheater into one of the rear seats as we felt this
would be more secure. The propane bottles have been placed in the rear
baggage compartment.

One of my partners is concerned that carrying either flammable bottles
or even just the preheater in the plane might cause insurance issues if
there were ever an incident.

Has anyone had any experience with these setups? Do you know the FARs
for carrying a preheater? What about the fuel?

Thanks.