Hi mate-yep, the A340 can be used without the ECU, although you do need to supply some power to the two shift control solenoids in the box. Without any power connected, the box shifts 1-3-4 when you shift the stick 1-2-D.
You can either build your own circuit to supply the solenoids with power (relatively simple-and I can go into a bit more detail if you want to go down that road), or you can buy a 'shift box' to do the job from MV autos here in adelaide. (both these options make the box full manual shift)