protected function getVirtualFolderCollection( $currentSite, $collection, $fullPath, $depth, $properties )
    {
        if ( !$collection )
        {
            // We are inside a site so we display the virtual folder for the site
            $entries = $this->fetchVirtualSiteContent( $fullPath, $currentSite, $depth, $properties );
            return $entries;
        }

        $collection = $this->splitFirstPathElement( $collection, $virtualFolder );

        if ( !in_array( $virtualFolder, array( self::virtualContentFolderName(), self::virtualMediaFolderName() ) ) )
        {
            return false; // self::FAILED_NOT_FOUND;
        }

        // added by @ds 2008-12-07 to fix problems with IE6 SP2
        $ini = eZINI::instance();
        $prefixAdded = false;
        $prefix = $ini->hasVariable( 'SiteAccessSettings', 'PathPrefix' ) &&
                      $ini->variable( 'SiteAccessSettings', 'PathPrefix' ) != '' ? eZURLAliasML::cleanURL( $ini->variable( 'SiteAccessSettings', 'PathPrefix' ) ) : false;

        if ( $prefix )
        {
            $escapedPrefix = preg_quote( $prefix, '#' );
            // Only prepend the path prefix if it's not already the first element of the url.
            if ( !preg_match( "#^$escapedPrefix(/.*)?$#i", $collection )  )
            {
                $exclude = $ini->hasVariable( 'SiteAccessSettings', 'PathPrefixExclude' )
                           ? $ini->variable( 'SiteAccessSettings', 'PathPrefixExclude' )
                           : false;
                $breakInternalURI = false;
                foreach ( $exclude as $item )
                {
                    $escapedItem = preg_quote( $item, '#' );
                    if ( preg_match( "#^$escapedItem(/.*)?$#i", $collection )  )
                    {
                        $breakInternalURI = true;
                        break;
                    }
                }

                if ( !$breakInternalURI )
                {
                    $collection = $prefix . '/' . $collection;
                    $prefixAdded = true;
                }
            }
        }

        return $this->getContentTreeCollection( $currentSite, $virtualFolder, $collection, $fullPath, $depth, $properties );
    }