Im not sure how i can specify this option using s3cmd implementation of s3cmd jail. I was using Standard_ia storage class for backups and now i want to use s3cmd to sync files but i found this problem.
Problem is i dont know how can i enable option storage class within jail API. i tried to use the command like i was using in aws S3 API and is not recognized.
I don't think the current API supports that. You could make a feature request at bugs.freenas.org asking that the next version of the API adds that support. If you do, post the issue number here.