How can I get clickable text with no marking

I'm displaying a bunch of text(*), and I want to make one of the words
clickable. I tried using <s:a>, but that makes the word stand out: a
different color and underlined. I want the player to have to read the
text and figure out which is the "magic word". I've set the color to
white (like all the other text in the frame) and set textDecoration to
None, but it's still showing up in blue and underlined.

<s:a href="GHen.swf" id="linkMainMenu" fontSize="14"
textDecoration="{TextDecoration.NONE}"
color="0xffffff" click="gotoMainMenu()">magicword</s:a>

Is there a way to do this -- to make one word in a bunch of text
clickable but not marked in any visible way? Or should I format the
page with HTML and convert it to an image, then overlay a button with 1%
alpha in the position of the word? Or something else?

(*) I'm using a s:RichText control to format my text, but I'm willing to
use something different if RichText can't do it.