(AGI) Hanoi, Sept 24 - Washington is to lift an arms embargo onits former enemy, Vietnam, to help Hanoi deal with navalchallenges from China. Foreign Minister Pham Binh Minh willvisit Washington in October for talks with Secretary of StateJohn Kerry and U.S. Defense Secretary Chuck Hagel is expectedto visit Vietnam later this year. Vietnam has two Russiansubmarines and plans to buy a third. . .