If you're just looking for a way to view/edit the HTML code, you can extend the RichTextEditor component and add a button to show the HTML.
All you need to do is set the textArea's .text value to textArea.htmlText, and you'll see the code. If you aren't already aware, though, that AS doesn't format using strictly HTML, you may be a little surprised by what you see. But, it's editable, at least.
