Allowing yelp to view docs for app installed in separate directory

[Albert Chin <gnome-devel-list mlists thewrittenword com>]

If I install gnome-2.8.2 to /opt/gnome28 and evolution-2.0.3 to
/opt/evolution20, how do I get yelp->Applications to see the Evolution
documentation in /opt/evolution20? I have Evolution working
successfully out of /opt/evolution20 but I'd like to get yelp to see
it's documentation (invoking yelp from within Evolution displays the
Evolution documentation just fine).

-- 
albert chin (china thewrittenword com)