Convoy Sun Hei face a tough task in taking on Al Wihdat of Jordan in the second leg of the AFC Cup quarter-finals at Amman International Stadium tonight. Having lost their home leg 1-0 a week ago, the Hong Kong side's chances of reaching the next stage seem remote. But coach Koo Luam Khen remains defiant. 'It is difficult but not impossible,' said Koo. He said the players were in good shape after the victory over Happy Valley last Friday night, and only Hong Kong international midfielder Lo Chi-kwan could not make the trip, due to an ankle injury.