createdDateTime field not showing in Aif document services


I created an Aif document service to export data from PurchTable and PurchLine tables among wich, the createdDateTime field.

The field is present in my query.

After generating the service, I added a parm method in the AxPurchTable class, exists and parm methods in the ServiceName_PurchTable class.

Yet, after registering the service, when I want to configure the outbound port, the createdDateTime field doesn’t show in the Document data policies form.

I can see the createdDateTime field shows on other services. So what I am doing wrong, or what could be missing in order to have that field showing in the data policies of my service.

Thank you for yours answers.