Adding additional fields to Delivery Due List

If you would like to add additional fields to the Delivery Due List - Transaction VL04. 
These fields do not exist in the list of additional fields in the IMG.
You will need to have a user exit written.
This OSS notes will help you in creating the additional fields :-
198137 - VL10: Customer-specific enhancements / user exits
415716 - User exits in delivery processing