Some things to try:
1. Install the "usb-modeswitch" and "usb-modeswitch-data" packages if not already there (check spelling/hyphens in the names I typed) and try unplugging and replugging it in.
2. In a console, run "tail -f /var/log/kern.log" to see what gets printed as you connect the device, it should print some USB device IDs like 1234:5678 which you can google for to see if its even supported.
3. Not sure about "kies" mode, you could also repeat the steps in any other/normal modes for the phone?