Wow, quite some traffic in this thread ...
As I mentioned, I can now use API-Calls to find "my" parent window. Just curios, which call will be, Dll-Calls to get Process list and than look for the window handle of the LabVIEW application or use the "Get HWND and PID" and obtain there the "MaiWindowHandle".
BTW, I also added a progress bar example of the TaskDialogIndirect.
I also tried to implement a few "NamedPIpe" functions. Perhaps you guys can have a look? Especially the Named Pipes (I only found some old code, using a wrapper dll, which I did not want) will not work ... Even I thought I just translated the examples of msdn (https://msdn.microsoft.com/de-de/library/windows/desktop/aa365588%28v=vs.85%29.aspx https://msdn.microsoft.com/de-de/library/windows/desktop/aa365592%28v=vs.85%29.aspx) to LabVIEW code...
WinAPI.zip