motion tween (fade) text converted to symbol no "motion"

I am using flash mx and my file includes text that is supposed to fade in and out.

I do exactly as I do with images - alpha 0 fades into 100 % etc, and it looks fine on the stage, but when I publish the text simply pops on and off with no recognition of the alpha channel fading in and out.

I create the text as static text - old english font - and then I convert it to a symbol. I tween the symbol from 0 to 100 alpha and back again. Presumably making it a symbol essentially makes it an image, right? no?

I am relatively new to flash so I may be missing something obvious?

(yes I have checked out places like flashkit.com, but not exactly what I am looking for, want more control.)