you would have to dynamically create your text fields then contol them using TextFormat. Here's a snippet from the flash help files for createTextField.

Code:
this.createTextField("my_txt", 1, 100, 100, 300, 100);
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 = "This is my first test field object text.";
my_txt.setTextFormat(my_fmt);
ps to the best of my knowledge TextFormat only works on actionscript created text field like the code above, but i've never tried applying it to a textfield made in the work area so it may work that way too.

good luck!