On of the downsides to Mac is that the Chinese-based manufacturers who implement what another country (I’m looking at you, Isreal) invents, well, they don’t tend to have new/recent Macs. This translates in Mac software for less-common devices being rather crappy, despite the benefit of one release variant.
So I’m working on Mobile broadband, on an Huawei E160, MacOSX-10.5.7,
O2’s software seems to be making a lot of failing system calls; I don’t think they have the same software, so I found the E160/2009-05-10 software on huawei.com Somehow, Huawei figured that an EXE file worked on Mac. Hmm. Maybe someone else is avoiding QA.
In trying to get this going, I started to think like a WIndows developer: I actually rebooted to see if it would make a difference. I haven’t rebooted in weeks (I think 5 weeks). No help.
In taking a break, I went to re-activate Airport Sharing, and there was a Huawei Modem! …so I clicked there, set the username, password, and dial-up number that is in the O2 documentation, and it works fine.
I then right-clicked the on-the-USB-disk, that appears like a CD and has the app software, and selected “remove from sidebar”. Maybe it won’t pop up every time I plug in.
Success!

Huawei Modem Happily Connected