Nautilus, MIME and .desktop files

[Rick L Vinyard Jr]

I'm having a problem getting nautilus to recognize a xournal PDF 
annotation file. I have the MIME type specified in the .desktop file and 
thought I had all the entries in the spec to install the desktop file 
and update the MIME database.

However, nautilus still recognizes .xoj files (the PDF annotation file 
that Xournal stores PDF highlighting and markups in) as an archive... 
needing to be opened with "Archive Manager".

Any ideas how to fix the problem?

Also, what would be necessary to get nautilus to use a specific 
file-type icon for xournal files?

Here's the desktop file:

[Desktop Entry]
Encoding=UTF-8
Name=Xournal
GenericName=Xournal Notetaking
Comment=Take notes, sketch and annotate PDFs
Exec=xournal %f
Icon=xournal.png
Terminal=false
Type=Application
StartupNotify=true
MimeType=application/x-xoj
Categories=GNOME;GTK;Application;Office;Graphics;Utility;

In the spec (install section), I have:

%{__install} -D pixmaps/xournal.png 
%{buildroot}%{_datadir}/pixmaps/xournal.png
desktop-file-install --vendor fedora \
        --dir %{buildroot}%{_datadir}/applications \
        --add-category X-Fedora \
        %{SOURCE1}

and also in the spec:

%post
update-desktop-database %{_datadir}/applications

%postun
update-desktop-database %{_datadir}/applications