Ok. Thank you for the help.
I try now LW 5.4.3 (no beta). It allow me to add my iTunes library indeed but as you said too, the librairy is not Shared. I didn't find any option to shared the content of this new library. Fortunatly, it has accepted the Drag& Drop.
Don't be too impatient because if you have a huge librairy, it can take some time before the content will be copy into the Public Shared folder...
Thanks again Lord of the Ring...