I just spent two very unpleasant days trying to get the T-Mobile ExpressCard IV to work with Vista 64. But for some reasons the T-Mobile drivers for the Huawei E870 are screwed under 64 bit.
Today I got a tip that I should try to install the latest version of Vodafone Mobile Connect which also includes drivers for the same hardware. And bingo this works. You can isolate the drivers from the Vodafone program files and uninstall Mobile Connect afterwards. awesome…
So you have to install a Vodafone software package to get T-Mobile hardware to run. Is that weird?