Hi
If you are using version 3.xx then you are lucky if you can even get it to scroll in ANY direction! 
On my system, sometimes it does and sometimes it doesn't. More often than not the text completely disappears!
It only appears if it is set to No Scroll. I can position it and that is all.
You should be able to produce a "typewriter" effect if you create an image for every letter addition and change of position and playing each one rapidly in sequence, setting the duration of each image to something suitable.
Nat