The best solution would be to query this namespace in WMI, from which I can report on compliance as opposed to whomever decrypts their drive.
Does LANDesk do that?
So I have created a custom vulnerability that shows when laptops (can be altered to as I have a custom product for laptops) that will show a device is vulnerable if Bitlocker has not fully encrypted a drive. I'm not that strong in VB (autoit man) but it seems to work. Send me an email and I will forward you the custom vulnerability for testing.