For a very low cost, to copy your LX 'GO' button function, you can use this USB relay
http://www.ebay.co.uk/itm/USB-Relay-Con ... OU:GB:1123
controlled by an RS232 command (actually two - relay_on followed after 100ms, say, by relay_off).
Our LX desk already includes a port for a remote 'GO' button, but you could wire the relay in parallel with your actual 'GO' button if necessary.
Good luck,
Dave
I have no connection with the manufacturer, but I have bought and used the above relay as described.