How do I use multiple output busses in JACK (Standalone audioplugin)

Linux
1

Hello

I am creating a simple crossover audioplugin. For testing I would like to use JACK since vst3 isn’t yet supported in linux (for the juce audiopluginhost).
I set the processor like this

 : AudioProcessor (BusesProperties()
                     #if ! JucePlugin_IsMidiEffect
                      #if ! JucePlugin_IsSynth
                       .withInput  ("Input",  AudioChannelSet::stereo(), true)
                      #endif
                       .withOutput ("Low", AudioChannelSet::stereo(), true)
                       .withOutput ("Mid", AudioChannelSet::stereo(), true)
                       .withOutput ("High", AudioChannelSet::stereo(), true)
                     #endif
                       )

But when I check in qjackctl or Carla only one stereo bus is visible? How do I make this work?