Sometimes software can not be exported due to ITAR (International Trafficing in Arms Regulasions) without an export license. Getting one for video or computer games can be a hastle due to computer algorithms. An "artillery training video" would not only be scrutinized for software issues, but also for content.
I design stuff for the military that goes boom, so we get ITAR trained to the point where we are ready to vomit when hearing the word mentioned. The State Department takes it seriously, and the depth of the senarios that are ITAR controlled are surprising. For instance, imagine trying to return a rifle scope to Nikon in Japan. They made it, they know all about how to make it, but since it is a rilfe scope, you would need approval from the State Department before passing the technogy (the rifle scope) to a foreign national (i.e. Nikon).
So, that may be the reason why they won't sell it outside the US.