Flash MX 2004.
text.embeddedCharacters
Property; a string that specifies characters to embed. This is equivalent to entering text in the Character Embedding dialog box.
This property works only with dynamic or input text; it generates a warning if used with other text types.
Note: Beginning in Flash Professional CS5, font embedding is controlled at the document level instead of the text object level. Use the "fontItem.embeddedCharacters" property instead of the text.embeddedCharacters property.
The following example assumes that the first or only item in the current selection is a classic text object and sets the embeddedCharacters property to abc:
fl.getDocumentDOM().selection[0].embeddedCharacters = "abc";