How to get camera highlight threshold, gain and saturation via SDK?

I am having difficulty retrieving the After Effects camera highlight gain, threshold and saturation values from the camera options, using the SDK.

I can get these just fine:

    bool   dof_on    = getStream(AEGP_LayerStream_DEPTH_OF_FIELD, 0.0) > 0.5;
    double focus_dist = getStream(AEGP_LayerStream_FOCUS_DISTANCE, zoom);
    double aperture   = getStream(AEGP_LayerStream_APERTURE,       0.0);
    double blur_level = getStream(AEGP_LayerStream_BLUR_LEVEL,     100.0);

But when I try to get these, I get an error saying they are undefined:

    double hThresh = getStream(AEGP_LayerStream_HIGHLIGHT_THRESHOLD, 255.0); // 0-255
    double hGain   = getStream(AEGP_LayerStream_HIGHLIGHT_GAIN,        0.0); // 0-100 %
    double hSat    = getStream(AEGP_LayerStream_HIGHLIGHT_SAT,          0.0); // 0-100 %

I am using the 2024 SDK I think - so not the latest but I hope that doesn’t matter.

Is it not possible to get these from the camera?

Thanks,

-Richard