Siebel CRM file system encryption

I need to find a definitive answer about the Siebel File System and whether it is truly encrypted or not. I see references that state the compression algorithm can be a "means of encryption" but then I also find documentation that if sensitive date is stored in the Siebel File System that you should use third party, or operating system, encryption. The Siebel CRM support team (here at my company) point to the Security Upgrade Pack, and the Enhanced Security Pack as well as the Hardening Guide, believing that if followed and installed means the file system in encrypted, however