Thanks for your answer.
You are right, your method sems be logic... but it's the part that I don't understand on side LOGIC PRO... I don't know where I can set these options.
It's a long time I try to solve this issue... but... difficult... I have my Prohet since 2 years, I never used correcly with LOGIC PRO. I use always another step ("internal instrument", record the event midi, copy/past the REGION to "External Instrument" etc... but it's not the best method.
That I found this afternoon (CET I'm french, in France)
If I set the PORT to NONE, I can hear the REV2 during recording. see file screenshoot attached.
But to hear it on the PLAY, I have to set the PORT to "Prophet" and select the right midi channel 2.
Also I found that if I select other midi channel I can hear the REV2 during the recording, but I send to other channel...
In fact, really I don't understand how use the "External instrument" with the PROPHET in LOGIC.
I hope meet here some people using LOGIC PRO X, and the REV2 in MIDI.
I repeat, I have an old Korg Wavesation, it's OK, with the Nord Stage 3, all is OK, and with Nord Drum3P all is ok.