Bob
Let me make a few suggestions. In your case they may not be possible, but I'll offer them anyway.
Go to the Remote Station, and verify that you can use SSB on the Remote K3. Make sure you use the same jack that the Remote Rig mike cable is plugged into. If you can't this to work when you are there, the chances of it working when you are remoting in is slim.
You shouldn't have to write anything down- if you used the same jack and it works, then there is no reason that the Remote Rig should not work. At least now, if the Remote won't modulate the radio, you know its not in the Remote Radio.
Go back to the remote site. BTW, I plug my footswitch into the PTT jack on the back of the K3Mini, and I plug my microphone into the side microphone jack. My SSB works fine. Let me know if this doesn't work for you, and I can more into my settings.
Dennis W1UE