Problems adding a desktop menu

I need to add a desktop menu in KDE to a number of FC4 machines to
hold Mathematical applications.  I read the menu spec at
freedesktop.org and cooked up the following, in
/etc/xdg/menus/applications-merged/uh-mathematics.menu:

<!DOCTYPE Menu PUBLIC "-//freedesktop//DTD Menu 1.0//EN"
 "http://www.freedesktop.org/standards/menu-spec/1.0/menu.dtd";>

<Menu>
  <Name>Applications</Name>
  <Menu>
    <Name>Mathematics</Name>
    <Directory>UH-Mathematics.directory</Directory>
    <Include>
      <And>
        <Category>Math</Category>
      </And>
    </Include>
  </Menu>
</Menu>

The /usr/share/desktop-directories/UH-Mathematics.directory file
contains:

[Desktop Entry]
Name=Mathematics
Icon=mathematics.png
Type=Directory
Encoding=UTF-8

I drop these, along with an icon, into a little RPM.

Now, this works fine: a new desktop menu named "Mathematics" appears,
and all applications with category "Math" appear there.  Great.  But
the Mathematics menu also appears as a submenu of Preferences and
System Settings and System Settings -> Server Settings, all with
identical content.

Any ideas on how I can get the menu, but have it appear only as an
Application menu and not all over the place?

 - J<