iTrip dock type connector volume trble

I have one of the iTrips that connects to the dock of my iPod Nano. It works well but I have one thing that really bugs me about it. It is sometimes difficult to hear some Podcasts and this particular model does not allow you to adjust the volume on the ipod itself, only on the car stereo. I have tried using "Gopod" "ipod volume booster" "eupod" None of these programs seem to do anything at all. I have even tried adjusting the volume on my library to boost the volume. Nothing seems to work. I think the other programs work well with iTrips that don't connect to the dock. Has anyone had any success finding something to use for the dock type connecting iTrip?