Help with motion tween mask glint

Ok well latly I have been having issues with getting a text mask where is masking gradient box underneth to show up in the test flash or in a final flash yet i can play it on the stage and it works. How I create it is first make two layers, name the top layer with the text and name it text mask. then the second layer i name it gradient box. I then put the font i want on the first frame of the mask layer, get the size and everything. Then on the first frame on the gradient layer I then make the rectangle the right size for it. Then I add a key frame to the end of each. Then I go back and move the gradient box so half of it is showing half of the box through the text mask. then on the new key frame i then move it to the other side. i then add a motion tween and mask the text box to the gradent box. i go to the control dropdown menu in flash and and click play to see it, but if i try to test it then it wont show up at all nether the box nor the text or what i want as the finished product. Anyone have any ideas why this might be ? Do i need to make ether of them movie clips ? do i need to tween the masking layer ? I am really lost on this so any help would be awsome. Thanks for all your guys time.