dhcpd.leases set ddns and windows

[andreas.moroder at sb-brixen.it]

Hello,

as I posted in April 2008 in our dhcpd.leases there are entries with  
this commands

    set ddns-fwd-name = "int-sek.sb-brixen.it";
    set ddns-rev-name = "252.5.53.10.in-addr.arpa.";
    on expiry or release {
      switch (ns-update (delete (1, 12, ddns-rev-name, null))) {
       case 0:
        unset ddns-rev-name ;
        break;
      }
      switch (ns-update (delete (1, 1, ddns-fwd-name, leased-address))) {
       case 0:
        unset ddns-fwd-name ;
        break;
      }
      on expiry or release;
    }

and others that don't have this part.
The strange thing is that most windows machines have the complete  
entry and some not.

Does anyone know what in the windows configuration is the reason the  
ddns part is missing in the dhcpd.leases file ?

Thanks
Andreas