No can do. Our wonderful media hates the word "terrorist" as it seems to imply that one side in this "War on Terror" (another term they hate) is actually wrong. Oh my goodness!
Of course, when you're beheading people and posting the videos online, or slaughtering hundreds of children at a time, it seems appropriate to say you're trying to "terrorize" your enemies into submission, rather than defeat them militarily. So "terrorist" might be a decent choice of words.
But then, I'm not a professional journalist so what the hell do I know?