Replace original OpenVR SDK with its modified version

Hi everyone!
I had added some functionality into OpenVR SDK source code and built my version of openvr_api.dll.
Now I wish to run my Unity project via this OpenVR dll, but I've stuck on thought where to place that dll?
I tried several places:

- Installed SteamVR directory: failed due to SteamVR uses proprietary version of openvr_api.dll (SteamVR crashes)
- Unity\Editor\Data\UnityExtensions\Unity\VR\ directory: failed, it seems that Unity just ignores my dll there.
- Plugin folder of builded project: the same result, application just ignores my dll.

What has worked? The sample openVR project which isn't compiles over Unity engine, it's just a simple OpenGL application and it loads and uses my dll to work with HMD.

I suspect that Unity Editor has staticaly linked OpenVR SDK and there is no way to run Unity projects via modified openvr_api.dll.

Somebody has any idea how to use my own version of openvr_api.dll with Unity?