240v Shore Power Connection

[sailcrazy]

Our boat(of 16 years) was built and used in Asia and the Med--until now. She is wired for 240v AC power,with a 3 wire sysyem-hot, neutral, and ground. We just arrived in the USVI, and plan to spend the next several years here in the Caribb. Unfortunately, the 240v(220-240v) available is based on a 4-wire system; 2 hots, neutral, and ground. Is there a way I can connect my 3-wire AC system to the 4-wire system we've found on marina power poles? We tried putting 2 wires to the "hot" and the third to gnd....we got 240vAC on the boat, but is shows reverse polarity, and switching the 2 "hot" wires did no correct the reverse polarity. Help!!!