ADDING A FIELD TO THE TRANSACTION ES32

Hi All,

I Have a requirement where i have to add a new field to the transaction ES32 at the billing document tab. i have find a customer exit EBIA0001 which is for custom defined fields at billing document level. is it the relevant one to add the field or is there any other way.  below attached file is the screen shot in which i have mentioned where exactly i need to add the field. Please help me find the solution.

Thanks and Regards,

Mohammed Farooq