Unfortunately the slate vendors have not agreed on a standard interface, so eepc only supports specific tablet hardware (Wacom powered). Anything else is up to the mercy of the BIOSmon the device.
Remember if you disable the preboot, you are storing the key on he machine, and thus are not really protected from data disclosure and protection regulations.
Thanks for the reply. This is a Wacom powered device and the pre-boot responds to pen movement but the calibration is off and the pointer travels faster than the pen. Also when the issue with the on screen keyboard still exists meaning it will not show up on the device unless I have the policy "force" the on screen keyboard. Then after that you still have the calibration issue making it hard to type in your credentials. If I cannot get the issue with the on screen keyboard to work correctly (i.e. pointer travels with the pen and on screen keyboard shows up when it is needed) I have no other choice but to bypass pre-boot authentication or find another encryption solution.
Good news! We were kinda stuck at this issue as well, but the latest patch for EEPC 6.2 fixes this issue.
BZ769612—Samsung Slate 7 tablets do not allow mouse movement at Pre-Boot.
BZ777682 - Add support for the Pen Digitizer from the Samsung SlatePC
To use this hardware device a policy with Pre-Boot USB support and On Screen Keyboard support enabled is required prior to enabling Pre-Boot authentication
We tested it out on our Samsung Slate 7 tablets and the pen calibration has worked successfully.