Call the simpleserver.php server instead of the server.php. Use the REST client demo and call simpleserver.php instead server.php. Set wsusername/wspassword parameters instead of the token parameter. That should be the only things to change in your REST demo client (in the condition that it was already preset and working). Also the user must have 'webservice' authentication method set. Note that you can not log into Moodle when this authentication method is set.