You've been there before... the report needs to be built with mixed formatting in the textboxes. Which one could consider a major gap with Reporting Services, because without doing some investigating and research, and in most cases coding and compiling of your own, this functionality simply isn't available.
While doing my own research into this, I found two sites that referenced the same C# code block that transform RTF documents into bitmaps and display them on reports. The first thread has a nice description and the second had nice pictures, neither of them had compiled code to download nor a working sample to verify... so I did that and have linked it to this blog.
I have found a sort of lazy man's beauty in this solution... because when I save a Word document as Richtext Format and then opened it in Notepad I could use all of the RTF code without any cleansing to build the images.
Hope someone else finds this as useful as I have.
** EDIT 2008/08/11 ** If you really want this to work, it is time to upgrade to SQL Server 2008.