Yes, turn on Bidirectional MIDI, and for any devices that you connect to the MIDI in port, make sure that the MIDI Port setting is set to MIDI In in the PBC's device settings.
You also need a special MIDI cable wired like this:
1 - 4
2 - 2
3 - 5
4 - 1
5 - 3
Custom cable companies like Best-tronics will be able to make it for you if needed.