DeviceReplay
You would find more on HP knowledge base:
http://www.advancedqtp.com/knowledge-base/articles/qtp-tricks4/the-undocumented-devicereplay/
Set deviceReplay = CreateObject( "Mercury.DeviceReplay" )
SystemUtil.Run "notepad.exe", "", "", "open"
' ** this line always identifies the notepad window.
Window( "nativeclass:=Notepad", "index:=0″ ).Activate micLeftBtn
deviceReplay.SendString( "DeviceReplay" )
Set deviceReplay = Nothing