Omniback - log backup to disk

Hi, We are backing up the log to disk via onbar and Omniback and the db in parallell using 2 devices. Omniback log retention is set to 24 hours, past that period the Omniback log devices on disk are recycled. A backup of the Omniback directories is done each day. I have been told by the Omniback administrator that it is impossible to perform a restore older than 24 hrs because the logs are no more on disk but on tape. And They can not be restore from the tape. I found this 'bizarre'. Any comments will be much appreciated. Regards Diane Lavoie