PPCGeeks - Freeware Mass Storage Program?

I've looked and can't seem to find any freeware programs like nueUSB that allow the PPC to show as Mass Storage but don't hide it from the device. It can work in an Read Only Mode, in fact I'd prefer that way, and it would be even better if it's just a setting I can change or a program that runs in the background. The problem I'm running into is I'd like to use my phone with my new head unit. It allows you to plug USB devices in and play music and video from them, however when I do this it hides the Card from the PPC, when TomTom starts it can't find the maps on the card and fails to load. I'd love to plug this in and let it charge from the HU while I play movies and music from it and at the same time use my phone as a GPS. Any help would be appreciate.