From: http://standards.freedesktop.org/menu-spec/latest/apc.html " Install desktop entries to datadir/applications/ for each menu item. Please namespace the filename, as in "vendor-foo.desktop", or use a subdirectory of datadir/applications/ so you have "vendor/foo.desktop. " So, either writer.desktop, impress.desktop etc. should all become openoffice.org-writer.desktop and openoffice.org-impress.desktop or they should all be installed in /usr/share/applications/openoffice.org
Turns out the upstream .desktops are namespaced, as openoffice.org-1.9-etc. Our's weren't because I short-cutted the OOo install and took the unprocessed and unprefixed .desktop files. Next spin will be as upstream and name them with the upstream openoffice.org-1.9 prefix