I have successfully connected HRD to a receiver on the remote server running linux. This is how I did it:
1) on linux, tcp to serial port server is a simple linux shell script. You will need netcat package installed (nc).
(stty $BAUDRATE -echo clocal raw pass8 ; exec nc -l -p $TCP_PORT) \
< $SERIAL_PORT > $SERIAL_PORT
2) Firewall on linux: block port 7805 being accessable remotely unless you want to open your rig to everyone or you're in secured network.
3) ssh, for example PuTTY. ssh to your linux box and port forward local port 7805 to localhost:7805 on remote system. This way you will tunnel your control traffic. Also, make sure your locally forwarded port 7805 don't allow remote connections. In Putty this is option "local port accepts connections from other hosts" being not checked.
... of course... you can skip 2) and 3) if your linux box is in secured local network and 7805 isn't accessable from Internet.
4) install any Com port redirector on your Windows box. I installed Lantronix software that is available free in http://www.lantronix.com/device-networking/utilities-tools/com-port-redirector.html. Create a local com port redirection (eg. COM3) to localhost:7805. If you skipped 2) and 3), create the connection to your linuxbox:7805.
5) Launch HRD... and connect to your virtual COM-port.