Manipulating Movies

If you create a movie clip and embed a textfield within it, can you then adjust the alpha of the movieclip in order to change the text display.

The code below attempts this but does not work…any suggestions?

clip = createEmptyMovieClip(“clip1”, 2);
clip.createTextField(“my_txt”, 1, 300, 20, 60, 60);
with (clip) {
my_txt.multiline = true;
my_txt.wordWrap = true;
var my_fmt:TextFormat = new TextFormat();
my_fmt.color = 0xFF0000;
my_fmt.underline = true;
my_txt.text = “Text.”;
my_txt.setTextFormat(my_fmt);}

clip._alpha=0;