I created a symbol and included a motion tween and it works perfectly (has the arrow), but when I try to play it on the timeline it doesn't play (you can only see the first frame of the symbol). When I test the movie the motion tween works fine. This never happened when I used Flash CS6 :S
In Flash Pro, Movieclip Symbols do not show the animation nested within them on Timeline and the full animation can only be previewed using Test Movie.
If you change the Symbol instance type to Graphic from the Properties Panel, you will be able the preview nested animation as well. (Just make sure that the frame span where your graphics symbol is placed is long enough to show the entire animation).
Thanks for your help!
You can also change the symbol type to Graphic, and it will, in fact, show the animation in synch with the parent timeline.