Setting Gnome mailto handler system wide?

[Mark C <lists funkypenguin net>]

Hi, 

I've managed to set system wide preferences for all the required gconf
settings using gconftool-2 on Debian Unstable, and that works great, I
cannot seem to find the settings I need to set the default gnome mailto
handler settings.

I can manually add the mailto protocol in :

Applications | Desktop Preferences | Advanced | File type and programs

running grep -r mailto .gnome*

produces the following file:
.gnome/application-info/user.applications

027c88d5-70ab-4202-b32e-7dc0384eec29
        requires_terminal=false
        command=evolution "%s"
        can_open_multiple_files=false
        name=Custom mailto

Also reading though the gnome-2.2 admin-guide, it refers to the section
I would need

http://gnome.org/learn/admin-guide/2.2/mimetypes-10.html

4.2.2.2. MIME Keys Files

As this matches what I found in my home directory, I tried adding the
required info to /usr/share/application-registry/gnome-vfs.applications

But it failed to take effect, also the file seems to be the one that
corresponds to the 'Registering Applications for MIME Types', rather
than what I'm after.

Could anyone can offer some advise or left me know of a tool or the file
I need to actually edit for this to take effect system wide.

Thanks

Mark