Here is a procedure for setting up CAS authentication and LDAP attribute retrieval :

CASsifier Sakai :

For sakai cassification you can refer to the documentation : http://confluence.sakaiproject.org/display/SAKDEV/CASifying+Sakai

Modify the sakai.properties file as follows to add CAS authentication and authentication for so-called guest members

=> here's my sakai.properties file

# ########################################################################
  # LOGIN/LOGOUT
  # ########################################################################

  # Include the user id and password for login on the gateway site
    top.login=false
  # Let the container handle login or not.
  # Set to true for single-sign on type setups, false for just internal login.
    container.login = true

  #
  # Login icon (uses container auth)
  # set to cas_login when CAS is in use
  #
    login.icon=/library/image/cas_login.gif

  #
  # Controls 2nd button (bypasses container auth)
  #
    xlogin.enabled=true
    xlogin.text=Invite
    xlogin.icon=/library/image/xlogin_login.gif

  # Logout icon
  #
   logout.icon=/library/image/cas_logout.gif

  # the URL to send folks to after they logout
    loggedOutUrl==https://serveur_cas/logout?service=http://server_sakai

    login.use.xlogin.to.relogin=false

Add LDAP to Sakai

Edit the components.xml file

SAKAI-SRC/providers/component/src/webapp/WEB-INF/components.xml
de-comment the following passage:

Edit the unboundid-ldap.xml file

SAKAI-SRC/providers/component/src/webapp/WEB-INF/unboundid-ldap.xml

Documentation

Sakai 20 LDAP & CAS Configuration

Add LDAP to Sakai