VMR9Allocator (DirectShow.NET + SlimDX)

I tried to convert and run the VMR9Allocator sample for DirectShow.NET with SlimDX instead of MDX. I got an exception when it reached this line

return vmrSurfaceAllocatorNotify.SetD3DDevice(unmanagedDevice, hMonitor)

      

        
        
        
      

    

In the AdviseNotify method in Allocator.cs.

The exception is

This interface is not supported.

and the return hr was

0x80004002

...

The sample works fine with MDX, and my SlimDx also works as I wrote other applications using it, working fine.

I can't seem to figure out what went wrong, no help from googling. Apparently not many ppl use this combination, not what I can find actually stumble upon this issue.

NOTE. I asked the same question on gamedev.net 2 weeks ago, no answer yet.