Batch input IDoc generation vs standard SAP transaction

Hello experts,

I am facing the following situation:

1. I developed a batch input program calling transaction WPUK and using an Excel file as the source of values. In particular the batch input calls Aggregated Sales option. When the transaction is called and values are filled, on Save button press no message for IDoc generation appears. No IDoc is displayed in WE02.
2. If I call directly transaction WPUK with the same data entered and press Save a message for the generated IDoc is displayed. Indeed the generated IDoc is displayed in WE02.
3. In table EDIDC there is a gap in the number range and this gap is caused by the "missed" IDoc which was not generated in case 1 (batch input).

Can somebody help?

Thanks in advance,

Konstantinos