protected function get_error_message_params( $key, $params )
	{
		// do we have a label to replace the key?
		if ( isset( $this->labels[$key] ) )
		{
			$field = $this->labels[$key];
		} else {
			$field = ucfirst( str_replace( array( '_', '-' ), ' ', $key ) );
		}

		return array_merge( array( 'field' => $field ), $params );
	}