I just wanted to inform that I created a short tutorial that describes, step by step, how to create a simple mission. The tutorial includes the relevant syntax from the mission file itself, so you can just copy from it and, if done right, test it.
You can find it as a sub menu under the "Documentation: Menu.
Hope it will be helpful.
I'll publish it later on the X-Plane.org under the Mission section.
Enjoy
Snagar