I recently bought a Huawei E180 Mobile USB Dongle, but immediately ran into problems. It wasn't recognized by the Mac and no matter what I did it faled to show up. After some research I stumbled upon a thread where they discussed a similar symptom.
It showed up that my earlier installation of a Huawei E220 Dongle somehow interfered with the new one.
- Delete /System/Library/Extensions/HuaweiDataCardDriver.kext
And then you're off.