oldciviregistrationplugin.php

<?php
// no direct access
defined( '_JEXEC' ) or die( 'Restricted access' );

jimport( 'joomla.plugin.plugin' );
// Could possibly be added to the civicrm system plugin
/**
 * This plugin will redirect from a com_user page to a civicrm registration profile.
 */
class plgSystemCiviregistration extends JPlugin
{
	/**
	 * Constructor
	 *
	 * @access	protected
	 * @param	object	$subject The object to observe
	 * @param 	array   $config  An array that holds the plugin configuration
	 * @since	1.0
	 */
	function onAfterRoute()
	{
		//Compare the request to the core registration request and if they are the same redirect

		$app = JFactory::getApplication();
		// Would want to change JRequest to JInput
		if 	 ((JRequest::getCmd('option')=='com_user') && 
		((JRequest::getCmd('view')=='register')||(JRequest::getCmd('task')=='register') ))
			{	// Redirect to the alternate registration page
						// Note you need this param in the sml
						$app->redirect($this->params->get('altregurl', 'index.php'));
			};
	}
}