The letter simply relates to the restrictions that almost all manufacturers have about unauthorized foreign sales. Imagine if you were the guy who paid or invested a bundle for the rights to sell Hummers in that country and learned that GM let US Hummer dealers export cars into your territory. There's also the US/non-US emissions & safety issues.
When I was in the military, we could order American vehicles through specific American dealers affiliated with the Exchange system. It may have been for US delivery only. I forget, it was a while back.
Have you checked?