[LAU] Problem with input/output of the RME Fireface 802 sound card in Ubuntu Studio 20.04 with Jack

Hello everyone, I am new to this list and also new to Linux. But need Linux to play a virtual acoustic scene for studies with hearing aid users. First, about my setup. I have an RME Fireface 802 sound card that should drive 12 speakers in a speaker circuit. I use Ubuntu Studio 20.04 LTS as operating system and realize the routing via JACK. The Fireface is connected to the computer via USB and runs in ClassCompliant mode, because RME does not provide drivers for Linux. According to RME the ClassCompliant mode should allow in- and output of all channels also with Linux. The soundcard is recognized and I can also use 8 output channels for playback. But I need all 12 output channels including the two headphone outputs. JACK recognizes 22 channels or shows them in the graphical user interface. But the outputs 1 and 2 of the Fireface do not provide playback and no input is recognized. Does anyone have experience with the Fireface 802 in Linux or had a similar problem with an RME soundcard and can help me? Thanks for any feedback! Best regards, Sebastian