CAN WE USE THE SHUTTLE BUS TO VISIT HONG KONG

We are flying from South Africa to Hong Kong and arrive at 7:30 the morning. We can only fly out to Phuket at 3 o clock the afternoon. We dont want to sit on the airport for 7 hours and would like to go into Hong Kong for about 5 hours time. Can we use the shuttle bus services for this purpose and where do we get the bus at the airport? We used this service in 2009 when we also flew with Cathay Pacific and want to know if it still possible to do it like this or what else do you suggest?