Assign to Item Categories for SD Deliveries not working VI63

Hi,

I have got a task to exclude specific item categories from Intrastat like TANN e.g. that are free of charge. Via VI63 I have set the indicator (01 - Intrastat exclusion) for the particular ones. Now when I create the order + delivery I see that nothing has happened. The indicator field in the delivery :
item data -> Foreign Trade/Customs-> Declaration/Values -> Exclusion/Inclusion is still empty.
Do I need some further settings?