Difficulty with Masking Technique

Hey everyone! I need to show my client an option where I am having text fade in via steam and I have tried a number of masking options to try and get this to work without luck. I have two layers with separate animations in each (set up as symbols, currently set a movie clip) one is steam and the other is a digital typeface (bitmap image). If I could get any masking to appear in my HTML5 i would be able to manipulate it for effect, but it doesnt matter whether I mask one to the other, use a movie clip or graphic, standard or motion tween, I can not get these two to mask together. Any thoughts or advice? Files attached... Thanks for the help in advance! Nick