6.3版好象是用事件驱动的:
//////////////////////////////////////////////////////////////////////////////
//
// 函数: OnFirstUIBefore
//
// 事件: FirstUIBefore event is sent when installation is run for the first
// time on given machine. In the handler installation usually displays
// UI allowing end user to specify installation parameters. After this
// function returns, ComponentTransferData is called to perform file
// transfer.
//
///////////////////////////////////////////////////////////////////////////////