reg screen exit in me21n using mm06e005

Hi,

I have implemented screen exit mm06e005 i added 2 fields at header level and 1 field at item level

every thing is fine but only thing is

I kept all fields are required but it is not generating any error message until unless if we got to the custom tab.

Please tell me how to validate with out going to that custom tabs.

Regards

Suresh