Not exactly sure how you where planning to display that HTML content in relation to the overall page, but given the limitations of Flash... that may just not be possible...
But, it would be a simple matter to display an HTML iframe over the top of or behind a Flash .swf... So while the iframe would not be a part of the .swf, it certainly could be designed to make it look as though it were.
Controling the stacking order or layering of content on a Web page is accomplished through z-indexing. Correctly positioned and z-indexed, the iframe could apear over the top of the .swf... the .swf in effect being the background... OR the iframe could appear behind the .swf and with a transparent section in the .swf, the iframe would appear through that hole. If there is navigation or links in the iframe, they will be blocked by the .swf though.
But this may be an option....
Thanks for your kind reply.
I'll check & try and let me come back.