WASHINGTON - North Korea's missile tests and menacing rhetoric have disappointed US expectations that young leader Kim Jong-un would be different than his father but Washington still hopes to persuade Pyongyang to change course, US Secretary of State Hillary Clinton said on Tuesday."With a new young leader we all expected something different," Clinton said in a town hall-style session put together by the State Department and broadcast worldwide. Last week North Korea declared a boycott of all dialogue aimed at ending its nuclear program and vowed to conduct more rocket and nuclear tests with its "sworn enemy" the US as the target.