Interface for Volume intensity

I am a developer writing a video capture and audio capture device. The devices already work in other encoders. The devices are written in directshow. I am integrating with FMLE and encountered this problem.

The audio device doesnt have a usable volume bar in FMLE. The FMLE error is "The selected audio device "censored (company secret)" doesn't allow setting volume intensity. Disabling the volume slider control."

my audio device implements these interfaces along with the standard directshow filter interfaces

IBasicAudio

IAMAudioInputMixer

I put tracepoints in my query interface and found FMLE query's for (my comments in comment string)

{IID_IUnknown}

{IID_IPersistPropertyBag}

{IID_IBaseFilter}

{IID_IAMOpenProgress}

{IID_IAMDeviceRemoval}

{IID_IMediaFilter}

{IID_IAMBufferNegotiation}

{IID_IAMStreamConfig}

{IID_IPin}

{IID_IReferenceClock}

{IID_IMediaSeeking}

{IID_IMediaPosition}

{IID_IVideoWindow}   // WTF ?? query video window ?

{IID_IBasicAudio}

{2DD74950-A890-11D1-ABE8-00A0C905F375} // i think this is async stream,

What am i missing ? FMLE doesnt use IAMAudioInputMixer ?

Anyone know the exact interface which FMLE uses for Volume intensity ? . .I assumed it was IBasicAudio, but it doesnt seem to call any methods in there.

(last point to add, my capture device works fine, just annoying that the volume bar is disabled even though my capture device does indeed support IBasicAudio and IAMAudioInputMixer)