Split stereo instrument or FX track for ambisonic mixing

Hi I want to use DearVr or others for ambisonics but the panner only takes one side of a stereo pair. I want to split the output of my instrument tracks or FX - which are often different in each channel and process the two sides in the spatialisation, eg to have a stereo instrument or a reverb behind me. If I use the Multipanner, going to an ambisonic output, its doesn’t seem to encode, ie i can very basic panic “through” my head, but essentially no other effect