URL Handler documentation?

["Robert A. Knop Jr." <rknop pobox com>]

Is there any more documentation on how to define URL Handlers than is
available in what comes up in the Gnome Help Browser?

My problem is that I'm trying to define a mailto: handler.  What I did was
create a new handler with protocol "mailto" and command

  xterm -e pine "%s"

It mostly works.  When I click in Galeon on a mailto link, an xterm opens
up with a pine session running.  However, instead of just the E-mail
address in the "To" field, I get something like:

  mailto: gnome-list gnome org;

Ideally, I'd like the "mailto:"; *not* to show up in Pine.

Is there a way to do this?  Are there other variable substitution thingies
besides %s that one can put in there?  I haven't been able to find
documentation on this anywhere.

-Rob