The auxiliary plug under the riders seat is a white two wire connector. It will have both the male and female ends of the plug but it will not have two of the pins that go inside. Why they are not included I do not know. To use this plug you will need to come up with the pins or modify the connector.
Mike
P.S. I ordered the pins from here. http://www.easternbeaver.com/Main/Elec__Products/Connectors/connectors.html They do have a minimum order amount but if a few people get together it is doable.