Unfortunately this editor is not Open Source, but you will find a trial version at http://www.realobjects.de.
You have to place the "edit-on Pro" code into some directory of your web-server.
For instance: $PREFIX/jakarta-tomcat-4.0/webapps/ROOT/editonpro
Then you have to tell the CMS where it can find this code. In the case of the
Materials Science Publication this is done by an XSLT-variable:
$PREFIX/jakarta-tomcat-4.0/webapps/lenya/lenya/pubs/ethz-mat/stylesheets/Configuration/read.xsl