I have sent previously a message with answers to you and a sample RFT file, but it looks like moderators have to approve it.
In the mean time, I have found a workaround for my problem.
I use Stanza Desktop to convert RTF or PDF (you lose the embedded photos)
to epub format, and then use Calibre to add cover, synopsis, and regenerate the epub.
With this, the output is perfect and ebooks can be downloaded to Stanza on Ipod
without problems.
Even more, my wife has gifted me an Ipad, and since Calibre can upload
the books to iTunes, the ibook stand looks awesome (although too much
big margins).
Thanks, anyway I will check your suggestions and let you know about
so I can stop having the need to use Stanza Desktop.
This is just a quick dirty trick just in case somebody has the same problem than me.
Just to note: Current Stanza Desktop has the nasty behavior of inserting the title
and author metadata randomly in paragraph beginnings along all the book (even in middle of the text) when exporting to Epub. Fortunately, using "decompress" feature on Calibre and "batch replace in all opened documents" with notepad++ allows to solve that quickly