I succeeded! I had problem with USB socket,...here the my procedure:
(for my MacBook Pro (OSX 10.9.2) one USB socket did not recognize the BS and names in the "Audio MIDI Setup" the device as "Device MIDI/USB". The other one works fine (for me) and 'see' the BS device as "Beatstep Updater").
-plug the BS (holding START/STOP buttons).
-open MCC and "Audio MIDI Setup":
1) go to MCC and click button for Firmware Revision. MCC asks to locate firmware file, then it asks for unplug.
2) unplug the BS.
3) go to "Audio MIDI Setup" and remove the device named "Beatstep Updater"
4) go back to MCC, plug the BS (holding START/STOP buttons).
5) it works and you can sync.