Hi experts,
We need to add an extensibility field to the OPD Billing document, in order to select it in the application "Output parameter determination". The field has been created in the " Sales: Billing Document " Business context and marked as relevant for Billing document output management parameter determination :

The followed steps have been:
1.- Create two outbound messages: PRINT and MAIL for Billing documents:

2.- In the table settings we need to select a new column:

3.- We can only select the standard given fields, eventhough we have allowed the extensibility field for Billing document output management parameter determination:

Any idea?
Thanks in advance.