Hey Matt,
You have to downlad the latest firmware from creative's website, and then you have to set the unit to record "mic in" when you are in the recording menu of the jb3. Don't expect too much though, the pre section of the jb3 isn't much to write home about. Most of us use a seperate preamp. Also, I'm not familiar with that mic but I assume it is a dynamic mic. If so you should be able to make it work, but if it is a conser mic you will also need a way to provide "phantom power" so that it will pass a signal.
Good luck!
Matt