The message the applicant will receive after applying for a program looks like the following: 
The application material has been submitted successfully. But it appears
to be incomplete. Please remember (or ask your references if needed) to
submit the following additional item(s) as requested in the program ad:

        1 Publication List (by postal mail)
        etc.

These additional items should be submitted as requested in the program ad.

[Your dept's custom message for applicant goes here]

Thank you.
Dept Name, Univ Name
where the missing item list is generated based on the program requirements and it could be empty. In the latter case, the applicant will be told that the application is complete.