It works with Linux!
Making it work involves 2 things:
- Setting up /dev/rfcomm, which is setting up /etc/bluetooth/rfcomm.conf (and restarting the bluetooth stack) and
- Setting up the configuration for the modem.
In the latter case I used KPPP and it was very simple. The only issue I had was using 921600 bit/s is too fast and no modem is found. using 460800 bit/s was ok though.