SOUTH China's chances of recording a hat-trick of victories over their traditional rivals, Happy Valley, this season will be affected by the absence of midfielder Shum Kwok-pui from today's Esso FA Cup quarter-final at Mongkok Stadium. Shum, Ku Kam-fai and Loh Wai-chi all received one-match suspensions from the Hong Kong Football Association's disciplinary committee on Monday but South China appealed against the bans on Ku and Loh - and the punishment was adjusted to a $5,000 fine. So while skipper and sweeper Ku takes his place in the centre of the South China defence today and right-winger Loh takes a seat on the substitutes' bench, Shum must sit out the tie. And South China coach Raymond Ng Wai-man feels Shum will be a big miss. ''He has been playing very well this season and is the most improved player in our team,'' Ng said. ''He has always been strong defensively but his passing and his forward runs have improved a lot this season.'' Shum will be replaced in the centre of midfield by Au Young Ying-tsz, who usually plays at sweeper or full-back. Valley's goalkeeper, Australian Tommy Maras, should be well known to South China as the Caroliners brought him to Hong Kong as a replacement for Allen McKnight. When Maras arrived from Perth, however, he discovered that South China had already signed Dutchman Werner Kooistra on a 11/2-season contract, forcing Maras to seek employment elsewhere. The winners of today's quarter-final will play in next Sunday's semi-final at the Hong Kong Stadium against the winners of Thursday's quarter-final between Kitchee and Instant-Dict at Mongkok Stadium. The other semi-final in next Sunday's double-header will be between FA Cup-holders Eastern and the winners of Tuesday's quarter-final between Kui Tan and Voicelink also at Mongkok Stadium. Happy Valley (4-4-2): Tommy Maras; Hau Yiu-tak, Leung Sui-wing, Wang Dongning, Keung Wing-yiu; Wong Fuk-wing, Alan Reis, Leung Nang-yan, Ricky Cheng; Darren Tilley, Simon Collins. South China (4-4-2): Werner Kooistra; Chan Ping-on, Marcel Liesdek, Ku Kam-fai, Chan Wai-chiu; Au Wai-lun, Au Young Ying-tsz, Chiu Chung-man, Wu Qun-li; Anto Grabo, Alen Bajkusa.