public function getHeader( $key, $first = NULL )
	{
		$fields	= $this->headers->getFieldsByName( $key );											//  get all header fields with this header name
		if( !$first )																				//  all header fields shall be returned
			return $fields;																			//  return all header fields
		if( $fields )																				//  otherwise: header fields (atleat one) are set
			return $fields[0];																		//  return first header field
		return new Net_HTTP_Header_Field( $key, NULL );												//  otherwise: return empty fake header field
	}