Override AdvancedSearch Class file

Hi together,

we tried several things to override the easysocial Class for the advanced search but nothing succedded.

Please have a look to this example: https://gist.github.com/dongilbert/3237387

Finally we created a plugin with this content:

<?php

// no direct access
defined('_JEXEC') or die;

jimport('joomla.filesystem.file');


if (!JFile::exists($file)) {
return;
}

class PlgSystemAspSocialAdvancedSearch extends JPlugin
{

public function __construct(&$subject, $config)
{
parent::__construct($subject, $config);

$app = JFactory::getApplication();

JLoader::register('EasySocial/SocialAdvancedSearch', JPATH_ROOT.'/plugins/system/aspsocialadvancedsearch/advancedsearch.php', true);

}

}



In the file advancedsearch.php we copied the content from /administrator/components/com_easysocial/includs/advancedsearch/advancedsearch.php

The main goal is to modify some things in the advancedsearch, especially the results of the search, because the search didn`t connect pages over the related pages field. And also to add a new type of option into the advanced search. We`ve found a workaround in the template but it isn`t the best way so far.
Could you please give us a tip what is wrong. We need to override functions for results and also override whole classes of easysocial to get our work done (We do NOT need Template Overrides!)

Thanks in advance