The radio on the Ultra and on the Streetglide are identical. On the Ultra, when you cycle through the options on the volume control it goes base, treble, fader then display. On the Streetglide everything is the same except the "fader" option does not appear. We hooked up a set of Bagger Audio Saddle Bag lid speakers. We used the unused plug (XM/Intercom/Rear Speaker Pods) on the radio to get the left and right rear speaker feeds. We had assumed by doing this that the "Fader" feature would activate but if we go through the amp or straight to the the speakers, they work, but the feature doesn't come on the display. Is there some kind of procedure we need to go through for the radio to "see" the rear speakers and make the "fader" feature work?