Provisioning multiple apps

Hello to all. I have successfully done the provisioning for one app to test on my device. My question is, I have one that is in development in xcode that I need to test on my device since I am using the gps receiver. Do I need to go completely through the provisioning portal again for the new app? I tried to just change the bundle identifier in the new app to what I set for the first app, but when I did a build and run, the new app overwrote the original.

Thanks for your input.