I have a client that have lost data in the past cuse he did not have a good backup strategy with oracle database.

I put his database in archivelog mode, duplex controlfile, logfile. A hot backup is made every night and vital files are put on tape.
The client is still insecure and wants a document that demonstrate that his backup strategy is oracle standard.

Have any idea where i can get that beside giving him the documentation of backup stategy from oracle?