IS_U_METER_READING_DOWNLOAD --- User Exit Include

Hi,

i have copied the IS_U_METER_READING_DOWNLOAD into ZIS_U_METER_READING_DOWNLOAD.

Here i want to write some logic on User Exit. But How to find User Exit in IS_U_METER_READING_DOWNLOAD?

Please give me way how to find the User Exit for any application form in EFRM Transaction.

Regards

Balu