Foreign Trade Data Incompletion Procedure: Error Message

Hi,

I have defined an Incompletion Procedure on Foreign Trade Data and I have required an error message if the data are incomplete when creating a purchase document. Everything is ok, the system is issuing the red error message

EI002 - Foreign trade item data is incomplete

and still, I can go over it and save the purchase order.

What am I missing?

Thank you,

Horatiu