Hello, i got my keyboard working in garageband on my mac through the m-audio uno usb midi interface, and the sustain plugged into my keyboard has no effect on what im playing. I tried turning things on nd off and all that. Is there a setting I need to change?

do you mean a MIDI pedal plugged into your keyboard? if so then you probably need to assign a effect to the pedal before it can do anything because you need to tell it what to do, im not exactly sure how you do this but is your keyboard is like mine you have a program button or ''advanced functions'' and use the keys to program certain parameters my best advise is to look in the manual and try and find a similar topic.