I'm developing a simple facial animation player using Managed DirectX Mobile that loads the model from a .obj file.
The problem is that a can´t use the default command

presentParams.EnableAutoDepthStencil = true;

to create the Depth Buffer because when I run my application setting the EnableAutoDepth true occurs an exception inside the device constructor.
The driver of my SmartDevice, that I use to test the application, doesn't support depth buffer to be created in System Memory.
I discovered this using the program D3DMobileDoctor that shows the driver capapabilities.
It shows this information about Depth Buffer:

SupportsSysDepthBuffer: False;
...
SupportsVidDepthBuffer: True;

What lead me to believe that the device constructor creates the depth buffer in the system memory by default, and what I need is to create the buffer in the video memory.

I didn't found nowhere a way to manually choose the pool where the depth buffer will be created and I don't think that it could exist.
If someone can help me find a solution.

Thanks! :P