THE Vancouver Port Corporation (VPC) is strongly promoting the concept of partnership in the port between terminals, unions, importers, exporters, railways, trucking lines and shipping lines. According to the Port News, a publication circulated by the Vancouver port, the Canadian transportation chain must function as an uninterrupted chain, linking seller to buyer rapidly and economically, if it is to operate successfully on a global scale. ''It must be of one mind and mission - to serve Canadian exporters and importers, helping them compete and win in this tough international arena,'' the newsletter said. It added that the issues facing Canadian transportation and the producers' ability to compete using that system, were immense but not insurmountable. These issues could not be heard individually but could be amplified by the ports, Port News said. It said the producers' case undoubtedly would be taken more seriously if they had full support from the transportation sector.