For reading easiness it is recommended updating the previews only after commiting the changes and on a different
posterior commmit, specially if the changes involve various docs.

In order to be able to generate previews you need to have the gentoo xsl files and gorg installed and configured.

Enter on the directory where you will hold the cvs docs
cd $PATH

First you need to get the xsl files, this is done with this cvs command:
cvs -d :pserver:anonymous@anoncvs.gentoo.org/var/cvsroot co gentoo/xml

Next you need to install gorg and configure it:
emerge www-servers/gorg
$EDITOR /etc/gorg/gorg.conf.sample

There change root = to this (don't forget to replace $PATH):
root = "$PATH/gentoo/xml/htdocs"

Finally save it as /etc/gorg/gorg.conf and you are done, now you should be able to use the preview scripts :D