I'm a newbie here. I got the D1 installed in my xA. I got a RCA to mini jack coming from the back of the headunit. went into the setting for AV and set to Video. Plug my Mp3 Player (sometime ipod, sometime my PDA)... i cant control the volume from the unit... only from my ipod or watever mp3 player i am using. is this correct?? or am i missing something?