Is there a way to disable the Windows Update in the unattendes install procedure ?

Either via a scipt afterwards or via the unattend answer file.

Today the windows update service is closed in the firewall, we are setting up a local sus server and until then no machine will be able to get the updates from the internet. It is annoying to have to disable it manually.'

Anyone any suggestions ?

There is an option in Winnt.sif:

[Data]
    AutomaticUpdates=no

but I don't think this will prevent you from getting pop-up telling you that Windows Update is not active....

The other way to do it with your Windows Server 2003 via group policy and then provide the update from your server with SUSadmin service... this will even grey out the Windows Update options in the System Property panel