Use ODBC API to retrieve indexes and keys on AS/400

hi,
i need to retrieve all indexes and keys from tables and files.
right now i'm using SQLStatistics, but it retrieve only the indexes on
tables (indexes that appear on the catalog sysindexes).
i need to retrieve also the key fields in physical file.

1. how can i retrieve the key field in physical file through ODBC?
2. Is there another AUTOMATIC way retrieving the key field? for example
a way to AUTOMATICLY transofrm the key field into index (so that
SQLStatistics will retrieve it)?


Thanks,
Dror