What format files do you want to include?
If you are talking about using html text, it could be possible by using a Flash text reader and using that. I am certain there are things like this available; if not, one could be made quite cheaply, so try freelancer.com.
You would need to add a graphic to your skin and assign it the attributes you want. Once published, you will need to edit the xml file (e.g. "text-reader.png") and replace the reference to the graphic ("text-reader.swf") with the name of the swf file that imports your text. It might be worth, dare I say, having a look at Arturo's html text box that he offer's for sale on the Pano2VR forum. If I remember right, this is an external swf that does exactly what you want. There is no reason why this cannot be used with an FFC project. But I am guessing.
I have to say that this is the most preferable solution, if such a thing is available, since it will provide the clearest rendering. However, if it is only small chunks of text, a graphic should suffice.