MiniDriver loading failed in protected mode

Hi,

We tried to generate a digital signature with our MiniDriver.
If the protected mode is active, Adobe does not load our MiniDriver in the process space. We do not receive error message.
If we deactivate the protected mode, our MiniDriver loading and signature creation will be successful.
We have found another MiniDriver (GlobalSign), which can create a digital signature in protected mode.
Our MiniDriver is signed by a Global Sign Extended Validation (EV) Code Signing Certificate).
Has got Adobe any requirement for loading MiniDriver in protected mode?
Thanks.