How to identify a third-party-order item in the invoice

Dears,

is there a figure in the invoice item which identifies one item as a third-party-order item? The item type TAS is not clear enough, because you can change the scheduled item type in the order from CS to another scheduled item type.

I don't find it because normally the scheduled item has the information, but in the invoice there is no scheduled item...

Thanks.

Chris