Cannot install Azure Active Directory Module for Windows PowerShell. MOSSIA is not installed

On Windows 8 or Windows Server 2008 R2, when trying to install Windows Azure Active Directory Module for Windows PowerShell you got the following error message (although Microsoft Online Services Sign-In assistant version 7.0 is installed) :

 "In order to install Windows Azure Active Directory Module for Windows PowerShell, you must have Microsoft Online Services Sign-In Assistant version 7.0 or greater installed on this computer"

NB : on a french server
"Pour installer le Module Windows Azure Directory pour windows PowerShell, l'Assistant de connexion de Microsoft Online Service 7.0 ou version ultérieure doit être installé sur cet ordinateur".

To solve the problem, you should install the beta assistant :
US : Microsoft Online Services Sign-In Assistant for IT Professionals BETA
FR : Assistant de connexion Microsoft Online Services pour les professionnels des technologies de l'information BETA

That's it.