Xponent & DJAY PRO ios : trouble routing audio

I connected my xponent to my ipad via the Apple usb CAM adapter.
Xponent works well under djay pro ios, but i have a routing problem for pre-listen
In the audio parameters of Djay, it only proposes xponent and xponent
Without separating channels 1 & 2 and 3 & 4
If I select master: xponent: the sound goes horrible with a permanent echo,
Pre listen: xponent: the helmet is perfect
The best routing I’ve found is to get out: the master by headset, and plug the headphones into the audio output of the ipad
It works but I can not adjust the volume of the headphones.
Any ideas, pléase

This works for me as well. My setup:

* iPad Pro 10.5"
* Lightning->USB adapter-> M-audio Xponent
* MIDI mapping file from DJ Tech Tools (https://maps.djtechtools.com/mappings…#) NOTE: you need to rename this file to “Xponent.djayMidiMapping” case-sensitive and without the XML extension, then you can upload to the iPad (DJay app) via iTunes
* Monitoring headphones attached to iPad headphone jack
* Master audio connected to L/R output on xponent

Specialy to employee who telling xponent doesn’t work on djay pro:
iPad PRO 12,3
lightning USB CAM
Xponent with djay pro 4 deck mapping (djtechtools)
Audio préf :
Master : headphone sélectes
Headphone: xponent
ALL is running like that.

Where I need to put the mapping in the itunes folders?
I’m talking about the last Djay Pro iOS app.
Also when you plug the xponent with CCK and hub how Djay shows it?
I’m not getting any midi signal with midi wrench and describes the xponent as MIDI USB Device but not loads any signal from it.