Whilst I agree that the RTF editor is somewhat unituitive it can be made to work and produce professional results. Let me outline some tips and tricks that I have found.
1) If you try to create one RTF template will all the details, all the formatting and headers and footers, you are on a hiding to nothing and banging your head against a brick wall.
2) My approach is to use the RTF editor to produce just the data. For example, I can create a RTF template that outputs (per package) details of all elements, (the name, author, notes etc) and if desired linked requirements
3) I create a "family" of such RTF templates, each addressing a portion of the overall documentation. So I have a template for diagrams, a template for elements, a template for linked requirements etc.
4) These RTF templates can have filters attached to "fine tune" the output
5) I then use "model documents" to target these RTF templates at specific package (or packages)
6) This results in a number of RTF documents
7) Now, over to Word. Create a outline documentation document including all formatting, headings, headers footers, standard text etc.

At the appropriate sections within the Word document, insert as a
file link the appropriate RTF file
9) A single RTF file can be used more than once in a Word document if necessary
10) If the model changes, regenerate the appropriate RTF(s) and then update the links in Word
Yes, a long winded process, but it works and in my opionion, a more productive way to use time than struggling with an editor than cannot do the job.
Incidently, the info from Sparx (white papers, user guide, on-line) seems to imply that the method I have outlined above is the way to use RTF documentation generation
I have conducted a number of training courses using the method above with great success