Premiere Pro CS6 will not natively support XAVC, but Adobe Premiere Pro CC, the latest version of Adobe Premiere Pro, has added support for this new camera format. If you stick with Premiere CS6, try to convert the XAVC codec to Premiere most compatible MPEG-2 codec using a third-party program.
I’ve had the pleasure of using the Video Converter for Mac (costs $27.96) to transcode the XAVC files from my F55 to work in my Premiere CS6 and FCP 7. You should give a try!