Sending an Async Printer Properties Request

The server MUST send the ASYNC_PRINTER_PROPS_REQ request message whenever the printing subsystem requests that the virtual printer driver display its custom printer properties UI. The contents of the Flags and hServerWindow fields are passed by the printing subsystem, where Flags indicates the state in which the printer driver's UI SHOULD be opened and hServerWindow identifies the parent window on the server in which the UI MUST be displayed.