I had similar problems,....
ok to get cargo to hook up u must hover land or be near the cargo to begin with, once u have done this,
bring up the radio comms \ , then select all cargos f6 , then select f1 in radio comms menu .
once you've selected the cargo, then go to external view , then select key commands right ctrl/ right shift and l key, you'll see the cargo being hooked up, now your ready to cargo lift.
for the cargo camera I have not been able to get this feature working yet myself.