[LAU] usb-audio-2.0 / class compliance question

Dear all, I already posted this question on other lists, so maybe one or the other has seen it, I apologize for sending it again. I have been trying to connect a friend's soundcard (RME fireface UCX) to my linux computer (recent ubuntu 12.04 installation - NOT ubuntu studio, kernel 3.2.0-29-generic, ALSA version 1.0.25). RME claims that the device has a class compliance mode, so that it should be able to communicate with a linux system just using the USB-audio-2.0 standard (which, to my knowledge, is available on linux). This class compliance mode works when the device is connected to an apple computer. Pluging the device, I get the following messages from dmesg: [ 864.024093] usb 1-1: new high-speed USB device number 5 using ehci_hcd [ 864.162776] usbaudio: unit 2: invalid UAC_FEATURE_UNIT descriptor [ 864.162831] snd-usb-audio: probe of 1-1:1.0 failed with error -5 The "lsusb - v" (quite lengthy, so I don't include it here) output lists the device, so it seems that it is recognized but can not be properly connected. It does not appear neither appear in the system settings nor in JACK. Am I missing some extra packages, libaries, ... to be able to have full USB-audio-2.0 support ? Do I have to change some kernel options ? Any other ideas ? Thanks, Florian