Unfortunately the camera has no option to set a pc mode or such. According the listing on the website of gphoto2, the camera-series where this one belongs to, is supported. It just should work with USB Mass Storage.
I found this in /var/log/kern.log:
Seems like the last line is the one where it's all about.
May 29 18:14:22 k-uptown kernel: [56955.444988] usb 3-2: new full speed USB device using uhci_hcd and address 9
May 29 18:14:22 k-uptown kernel: [56955.613217] usb 3-2: configuration #1 chosen from 1 choice
May 29 18:14:22 k-uptown kernel: [56955.630216] scsi9 : SCSI emulation for USB Mass Storage devices
May 29 18:14:22 k-uptown kernel: [56955.635198] usb-storage: device found at 9
May 29 18:14:22 k-uptown kernel: [56955.635207] usb-storage: waiting for device to settle before scanning
May 29 18:14:49 k-uptown kernel: [56982.182342] usb 3-2: usbfs: USBDEVFS_CONTROL failed cmd kio_kamera rqt 33 rq 102 l
en 0 ret -71