I have just installed the Windows 8 Assessment and Deployment Kit and came across some information about Windows 8 support for eDrive also known as the Encrypted Hard Disk Drive..
The Windows Setup Reference mentions a new setting called Microsoft-Windows-EnhancedStorage-Adm / TCGSecurityActivationDisabled. By default, when Windows is installed on an eDrive, Windows automatically encrypts the drive by using TCG and IEEE 1667 transport standards.
More information:
eDrive Device Guide
Almost All Future Drives Will Self Encrypt, Says Tom Coughlin, in Industry’s First Forecast on SEDs
Building hardware-accelerated encrypted devices (eDrives) in Windows 8