Today I bought the same modem as you. There seems to be no Mac driver available anywhere on the net, neither on the manufacturers webpage or the providers one (sunrise).
Solution Step 1: call sunrise tech support, they'll send you the Mac driver (NovatelWireless
3G_v20.dmg). I was told that the driver should be available on their support page in a few days.
Step 2: Install the driver. (Reboot)
Step 3: Unlock the SIM card using a cell phone.
Step 4: Insert the SIM card in the modem.
Step 5: Connect the modem to the Mac (it should show up as "Novatel Wireless HSUPA Modem" in System Preferences -> Network)
Step 6: Enter the telephone number in the PPP panel (*99# for sunrise)
Step 7: In the Modem panel, select Modem: WWAN Support, check "Enable error correction...", uncheck "Wait for dial tone..." , select "Tone Dialing" and "Sound Off".
Step 8: Connect to the internet...
This worked for me - spent only half an hour on the phone =).
HTH
-Urs