Where they will most likely have problems is heat build up in the aircraft on the ground if used in hot places. The DA42 has no aircon and so if you have long way to taxi or are held up at a holding point, then the guys are going to roast. Not a nice way to start a long flight. Once airborne the cockpit temperature gets a bit more reasonable, but is still fairly warm in direct sunlight.
Hardly the best aeroplane for anywhere such as Iraq or Afghanistan then....
Did you have anything more suitable than a Vulcan pee-tube in the cockpit with you for your 7 hour flights?
If the cockpit gets as hot as you suggest, presumably there will be a need for a lot of water to keep the crew hydrated for 12 hours? Where will that be kept - and how heavy will it be?
The use of such lightplanes in operational theatres is not as simple as the beancounters would appear to understand.