Xfce desperately needs a decent menu editor.
What about xfcemenuedit? Has someone already tried?
http://xfcemenuedit.mon-asso.org/index.en.html
I do not know if it works with Xfce 4.8 and above ...
There are also some nice hints, tips and tricks here and there. :)
http://wiki.xfce.org/faq#menu
http://forum.xfce.org/viewtopic.php?id=3795
https://wiki.archlinux.org/index.php/Xfce#Replacements_for_the_default_.2...
http://wiki.xfce.org/howto/customize-menu
Hope that it helps somehow. If not, please tell us your concrete
issue and what Fedora release you are using. ;)