First functionnal version of permissions handling! Many thanks to Django developers :D

scripts/populate.py

@@ -1,10 +1,15 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-from django.contrib.auth.models import Group
+from django.contrib.auth.models import Group, Permission
 
 if __name__ == "__main__":
-    for gname in ["DomainAdmins", "Users"]:
-        grp = Group()
-        grp.name = gname
-        grp.save()
+    grp = Group()
+    grp.name = "DomainAdmins"
+    grp.save()
+    
+    for pcode in  ["add_mailbox", "change_mailbox", "delete_mailbox", "add_alias", 
+                   "change_alias", "delete_alias", "view_domain", "view_mailboxes",
+                   "view_aliases"]:
+        grp.permissions.add(Permission.objects.get(codename=pcode))
+    grp.save()