Can I control my synthesizer with Touché via USB?
When Touché is in Slave Mode (connected to Lié via its USB Port), it always sends the CCs 16/17/18/19 via its USB port, because Lié need those CCs to speak with Touché.
If you want to control something via USB MIDI with Touché, you must use the MIDI re-routing functions of your DAW - if your DAW supports it - and select the CC you want to control with Touché by using a hardware preset in Lié.
In other words, Touché will still send the CCs 16/17/18/19 to Lié, but Lié will send the CCs that are specified in the selected hardware preset, to whatever track from your DAW you choose "Lié" as a MIDI input.
Then, send the MIDI from this track to your synthesizer using the MIDI routing function of your DAW.
Here is an example with Ableton Live and a DSI Tetra :
Please be aware that the forwarding of MIDI messages as described above will only work with the VST version of Lié and therefore isn't workable neither in Logic nor when using the AU-version of Lié within Ableton Live.