Qt 6.2.1 and Visual Studio 2019 error compiling moc_*.cpp files missing C++17 compiler defines

Hallo everybody

I had a project perfectly compiling on Visual Studio 2019 and Qt 5.15, now I'm trying to compile it against Qt 6.2.1.

I changed the version of C++ to C+17 on the C++ language section of the VS project settings page and I also added the /Zc:__cplusplus option to the command line of the C++ project settings.

Everything works fine until the beginning of the compiling of the moc_.cpp files generatated by the moc tool. Those files (moc_.cpp) are not included in the VS project so I think they are processed by the moc tool but I got the error:

fatal error C1189: #error:  "Qt requires a C++17 compiler, and a suitable value for __cplusplus. On MSVC, you must pass the /Zc:__cplusplus option to the compiler." (compiling source file .\GeneratedFiles\Debug\moc_offlinetransferform.cpp)

How can I configure the moc tool to use C++17? Is there a workaround for this?

Thanks

Marco