SINGAPORE (Reuters) - Asian shares slipped on Tuesday after a plunge in U.S. manufacturing activity hit American stocks and the dollar, while the euro hovered near a six-week high on optimism over Greece's plan to buy back debt. MSCI's broadest index of Asia-Pacific shares outside Japan fell 0.3 percent to 450.79, backing away from a nine-month high reached on Monday. Australian shares eased 0.5 percent, while Japan's benchmark Nikkei share average fell 0.2 percent, declining further from a seven-month intraday high of 9,525.82 struck on Monday. ...