To go along with what St Christopher said, wouldn't a civilian be better, perhaps even more desired, in certain situations? (religious and education issues are 2 things that come to mind). Yes, you could get a Chaplain, but someone in civilian clothing would probably seem more "neutral" to them. (especially if that civilian really knows and understands Islam)

Why aren't there more experienced diplomatic officers over there? Is it lack of training? Is it because the military doesn't want them there yet? (which I would find hard to believe) Or are there too few volunteering to go?