> So what's the story on propane in Europe. I was under the impression that
>> they used butane in Europe

At cooler temps, butane won't have enough vapor pressure to
be useful.  Here is a good site on the two:
http://www.e-lpg.com/lp_gas.asp
Butane boils at 0.6 degrees C; propane at -42 degrees C
If you have a butane stove such as this:
http://www.amazon.com/Burton-Portable-Table-Butane-Stove/dp/B0000DI5GD
it is useless below 50 (or so) degrees F.  As the stove uses
butane, the cannister gets colder and pressure drops.  I know,
we used one a lot in my '81 non-Westy; it is great stove, but
in Colorado it is usually too cold in the morning for the stove
to work. I'd have to stuff the cannister inside my jacket to
get it warm before making hot chocolate....

Anyway, propane for colder climates, butane OK for warmer.
Also, the pressure needs to be different between the two.
Look at the product specs for the Propex at:
http://www.propexheatsource.co.uk/heatsource.htm

Richard
Boulder