Union Number in Master data

Hi all,

Can anybody tell me how I can found out where the Union Number is maintained in the EE master data? We are planning to use this field in the Benefits feature (BSTAT) for a custom need. I checked infotype 0057 but not sure which field exactly represents the Union Number. Reasons,

1. No field says 'Union Number'

2. The technical info in the feature structure says its 4 character field but all the fields in IT 0057 with a number allowed entry of more than 4 characters.

Any guidance on finding out the exact location of Union Number in the master data will be a great help because it solves our custom need so easily. Thanks in advance.