MPC X - Midi From External Synths Back Into Box

Hi and thanks, in advance, for your suggestions and guidance.

I really like my MPC X and I'm trying to keep my productions "in the box" in standalone mode. How do I record the audio from external synths back into the track so that the project is self-contained in the MPC? For example, I'll record a midi track on track 2. Before I shut down, I want to record track 2's audio into the MPC so that I can save the entire project in the MPC. I believe resampling is the only way to do this?

Thank you all.

It works exactly as you suggest it should !
Create an audio track , send the synths audio output into the mpc inputs.
Expand the audio track and monitor the input level, adjust the rec gain with the rear pot.
Select your audio track , then Rec + play start
You're done.
You now have an audio track reflecting the midi track of your synth.
Don't play them together or you'll end up with a phase issue or way too much volume.
Mute the midi track or the audio track. Your choice.

This works only if MPC Live provides Master clock, if MPC Live (standalone) is Midi-clock-slaved it does not work!!