Time Evaluation & Unpaid Absence

Dear Gurus;

There is a requirement regarding the Time Evaluation & Unpaid absence.

They want whenever they are generating the Time Evaluation and the system finds that the employee didn't sign in or out in "IT2011" then it automatically affects absence type "Unpaid Absence" in IT2011.

How can this be done.

Thanks in advance.

Best Regards;

Lobna