well, i see that chris hasn't replied to this, so hopefully mine will do : ) both antennas are already connected to the stock headunit; i think that the radio switches between them based on which one is getting better reception. to keep your trunk-mounted antenna from extending, just pull the electricalplug that goes to it's motor. you can get to it by peeling back the trunk carpet on that side of the trunk, and you will see two things plugged into the antenna assembly: a thick black wire that is the connection to the headunit, and then a small gray plug that has three wires going into it - this is the power connection. if you just pull that plug whil ethe antenna is down, it won't extend any more (until you reattach the plug, of course). hope this helps,
wally
wally