well i'm planning on buying an apple 'dock' and i was hoping i could just plug the dock line out directly into a small sony 2 channel car amplifier. but the amp obviously has no volume control, so will the ipod wheel still work to control volume? i only ask because i was playing with a friends JBL home ipod speaker system and you can't use the ipod to control volume when it is connected to this unit.... make sense? or no?