http://www.dpawson.co.uk/fedora/oldandnew.html
Is the general writeup on using SGML tools to get from twiki to docbook.
I've described it in a general way, rather than tayloring it to Fedora usage.
Same directory, twikiFedora.xsl, if used instead of twikiStyle.xsl, will produce docbook with all the fedora stuff included. The only problem I haven't figured out, is resolving twiki files which don't have ---+ as their first element. Those starting with second level headings simply don't work. If needed, insert a level one heading prior to first content, then it all works. I'll update as and when I've figured it.
Comments appreciated.
regards DaveP