ORIGINAL: Rodney
It is not wise to use the Futaba connector on the Hitec. The Futaba uses a 5mmOD 2.1mmID (Radio shack part no. RS274-1567) while the Hitec uses a 5.5mm OD 3.5mm ID (Radio Shack no. RS274-1573) connector. You could buy the proper connector from RS and solder it in parallel with the existing connector on your Futaba charger and charge either safely with the same charger.
thats a real good idea