My modem is a huawei 220, and I never had serios problems with it - it worked with Gnome and only with Mandriva 2009/ KDE (not 2010!).
It is strange that it does not work correctly with the new releases- acccept centOS and openSUSE!
It worked without installing a program, so I never heard of usb-modeswitch; could you please give me a few details?
The Huawei E220 is really bad news: even a 2.6.31-15 kernel doesn't get it working on Ubuntu, and from what I've seen it always crashes a few seconds after being plugged in, making even usb-modeswitch useless. To top it off, on my PC the entire USB bus crashes when the E220 does, needing a complete reboot to get any USB device working again.
I managed to get my E220 working as follows:
Cold boot with the E220 unplugged.
sudo killall devkit-disks-daemon
sudo killall devkit-power-daemon
Plug in the E220 and wait a while.
Click on the NetworkManager tray icon, then set up and/or dial your connection in there.
If you connect but have no DNS, either disconnect and reconnect until you do, or manually set DNS up.