MPD Bit Depth Setting

[R101G]

I have volume disabled to give bit-perfect output from 16 bit sources, which is what all of my local sources and most radio streams are.
The MAD mp3 decoder outputs 24 bits and 320k BBC m3u8 streams are resolved to 32 bit, so I would like to set the audio_output_format to "*:16:2" in mpd.conf so that 16 bit sources are unaffected, but anything else is dithered down.

The custom settings in rAudio will allow the format line to be added, but so far as I can see will not allow the additional resampler settings to make it work.

Is there any way to stop rAudio overwriting the mpd.conf settings, which will allow the option of libsamplerate as well as sox?