Hallo Janos.
Note that if I revert to normal table, with the script SDBAD_IOTC_UNDO.sql , the problem still happens because it still use the statement "Create AS select ..." so the old default values are lost.
I think that the solution is to create a script, as suggested by Yves Kerdac" to restore default values for all my 150 tables.
However, I am waiting for SAP support what they tell me.
But SAP doesn't answer...
Thanks