I don't believe it is possible, but someone may wish to disagree. If it is possible at all, it would have to be hand-coded in the XSL.

Will you explain your reasoning behing wanting to do such a thing as this? Microsoft is always interested in learning how people are using their software so that they have ideas for future improvements.

I have a large rich-text box wherein I would like to
place a text box.   Is this possible?