I just bought an Ashdown FS-2 footswitch for my Evo III 500 head. I've been fiddling around with it trying to set up the footswitch, but whenever it is plugged in, it turns on both the valve drive and the octave, but the effect won't turn off. It appears that the footswitch makes the effects always on. Is there any reason to this? I want to be able to turn them off with the footswitch, but it won't turn off... Anyone experience anything like this???