Could it be the soundcard will not handle both audio from the radio and HRD at the same time?
That is likely the (or at least a) problem. Usually only one program running at a time can access the sound card, making it unavailable to other programs. Maybe you can disable the audio on the remoting program; you won't need it for digital modes if you can see the waterfall.
Looking forward to working you. Please save some time for us little (100 watts) pistols.