Multisite & quickupload

The FCKeditor is working fine, even in combination with the IMCE filebrowser. However, the Quickupload gives me a headache. The files are uploaded to the directory "sites/all/modules/fckeditor/fckeditor/editor/filemanager/connectors/php". Of course, this is wrong. The pictures should be in "sites/{sitename}/files/user/{username}". I searched for answers and i think the answer is in the config.php file of "sites/all/modules/fckeditor/fckeditor/editor/filemanager/connectors/php"

 * Configuration file for the File Manager Connector for PHP.
 */

global $Config ;

// SECURITY: You must explicitly enable this "connector". (Set it to "true").
// WARNING: don't just set "$Config['Enabled'] = true ;", you must be sure that only
//		authenticated users can access this file or use some kind of session checking.
$Config['Enabled'] = true ;

// Path to user files relative to the document root.
$Config['UserFilesPath'] = '' ;

// Fill the following value it you prefer to specify the absolute path for the
// user files directory. Useful if you are using a virtual directory, symbolic
// link or alias. Examples: 'C:\\MySite\\userfiles\\' or '/root/mysite/userfiles/'.
// Attention: The above 'UserFilesPath' must point to the same directory.
$Config['UserFilesAbsolutePath'] = '' ;
  require_once '../../../../../filemanager.config.php';

// Due to security issues with Apache modules, it is recommended to leave the
// following setting enabled.

But .. but .. i have several (multi)sites. Something like this
$Config['UserFilesPath'] = 'sites/example.com.directory/files/' ; does not work, because several sites are using this path. Is there a fix / workaround for this?

- maybe putting config.php in the /sites/{sitename}? Or replace the code in config.php into something like require(/sites/{insertactivesitename}/configphp