disappearing mobile broadband connection

[Roger49]

Hi,
I'm looking to switch to Xubuntu 12.04 from ubuntu lucid shortly, and I am having difficulties with my mobile broadband connection.
It is visible in connections manager on start-up, but when I attempt to connect, the "whirly icon" does its thing for a little while, then a message pops up that tells me mobile broadband is disconnected. After that, no mobile broadband option is visible in the drop-down list. Removing and replacing the dongle does no good. I have tried "lsusb" here is the result:

roger@roger-HP-Compaq-dc5100-MT-EC955ET:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 13fd:1840 Initio Corporation Shintaro SH23SDOCK Hard Drive Docker [INIC-1608L]
Bus 003 Device 002: ID 046d:c016 Logitech, Inc. Optical Wheel Mouse
Bus 001 Device 004: ID 12d1:1003 Huawei Technologies Co., Ltd. E220 HSDPA Modem / E230/E270 HSDPA/HSUPA Modem
roger@roger-HP-Compaq-dc5100-MT-EC955ET:~$

I would be grateful for any help on this, as this would be the basis for my desktop system for the next 3 years.
Regards,
Roger.

[howefield]

Thread moved to the "Networking & Wireless" forum.