I got an FBV Mk2 express pedal for Christmas which I'm trying to use with my Amplifi 75. Try as I might I can't assign the 4 tones I want to the 4 footswitches. Also am I really restricted to just one bank of 4 tones when there are 25 to choose from? Please help, if I can't make it do what I want I'm sending it back.