Comment 4 for bug 479343

JoanCF, the only think worked for me is:

1.- Create manually the band connection in network manager (with modem unplugged)
2.- Install usb-modeswitch && usb-modeswitch-data
3.- Unninstall modemmanager 3.0 (lucid lynx default)
4.- Download and install javier Martin modemmanager modified
http://ppa.launchpad.net/jmartinj/x060-karmic/ubuntu/pool/main/m/modemmanager/
5.- Restart
6.- Plug-in your modem, it will works, that's all folk.