Look here to see a breakdown of what your car has:
http://www.bmwvin.com/
It depends on what radio unit you have installed, if your iDrive has been updated, and if the option is coded as a feature.
First get your radio type to see if it's possible.
Look at your iDrive version and compare to the most current version for your car at:
http://www.bmw.com/com/en/owners/con...re_update.html
Finally, if that still doesn't solve your issue, it MAY be a feature the previous owner coded out. In that case, contact someone who does coding, like Apline. (Alpine Sales <alex@alpinemss.com>) For a small fee they will be able to not only check that feature but assist with any updates/codes you would like.