You can install the accessory outlet that uses a BMW style plug or you can purchase the GPS wiring harness which plugs into the main wiring harness under the tank and use that to power your Autocom. I use it to power my radar detector.
Some splice into the taillight wiring. On my standard Rocket there are a few plugs under the tank that aren't used. I used the head grip plug to pull power. Make sure you find a source that is switched with the ignition.