Visual Studio Build Tools 2017 not detected

I've just installed Qt Creator 4.4.1 and Visual Studio Build Tools 2017
with the 2015 and 2017 toolchains.

The 2017 toolchain is completely undetected by Qt Creator.
 
The 2015 toolchain is wrongly detected: Qt Creator uses vcvarsall.bat located in C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC. Instead it should uses the one located in C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Auxiliary\Build and pass -vcvars_ver=14.0 as a command line parameter. As a consequence the kit seems to be ok, but build will fails because "cl.exe" will not be found.