After a looong night of download, the entire library was properly installed and authorized. The installation process is actually simple, IF YOU KNOW HOW. First one must install the hosts (sampletank, syntronik, sampletron, miroslav miroslav philarmonik 2). When the installation ends, the product manager proposes to install the samples, even if you indicated a custom install path in the product manager, and this is where the confusion comes from. I refused the continuation of the process, and didn't install the samples. Instead, I opened the 4 hosts (sampletank, syntronik, sampletron, miroslav miroslav philarmonik 2) and configured the library path in each one. Once this was done, I then started to download and install the sounds. Once this was done and everything was installed, the authorisation of some libraries didn't work in sample tank, so I had to unauthorize and re-authorize the hosts and product manager, and finally, everything works.
Ow, I also had to reinstall Miroslav 2.0.5 because the newer version gave a "missing .vpa" error. The installation of 2.0.5 corrected the error, and then I cvould install the 2.0.6 version, and it worked.
I hope this helps. I wish IK Multimedia makes it possible to configure the library path installation directly from the product manager. It would be soooo much better.
One last thing, in order to install the full library (around 600Gb), you need 1.28 Tb of free space, because the product manager keeps both the installation files, and the installed files. You can delete the installation files manually, but product manager will not do it once the libraries are installed.
I hope this helps, and avoid to you what I had to go through, to finish this installation process.