Cubasis LE on IPAD Pro with USB Mixer/Recorder

Hello, I have recently bought a USB and Mixer audio Interface: Allen & Heath ZEDi-10FX.
I have plugged my guitar and a drum machine into it to record tracks on the Ipad Pro thanks to Cubasis LE.
The ZEDi-10FX is connected to the IPAD with an apple Camera Connector.
When starting the record, I have a very low volume on the tracks. It seems that only the microphone of the Ipad is defined as Input Source instead of the ZEDi-10FX.
What do I need to do to have the ZEDi-10FX as input source? Thank you. Benelolo.

Doublepost, please read here.