you can use this thermo-plastic (the granulate you drop in boiling water) to create a nice support for the cable.
I also made an aluminium plate that is screwed under the camera and goes about 1.5 inch far from the hdmi socket (in fact a bit more than the plug length.
there is a slot into the plate where a can slide the cable. on the cable i put a small spring so when the cable is plugged, the spring is compressed between the plug body and the plate, naturally pressing the plug into the socket.
I know it is tricky to understand, i will try to put a picture next time i use the camera.
