I have same problems with my modem on 12.04. All you have to do are the following things:
First install USB_modeswitch on your computer. Try to download it from Software Center or Synaptic package manager. Also check for
libusb in synaptic.
Now check whether you have
/etc/mod_switch.d file. Don't worry about their content, just check whether they are on your system or not. If
/etc/mod_switch.conf is not present then you can create it manually.
Now check the file in
/usr/share/usb_modswitch you will find a tar file in it which contain some information about your device. Look for your device file in the tar file, you will get it there.
To know which file you need, just run the command
lsusb in your terminal to get the
vendor id and
product id respectively. In your file you will get the information like:
You will have you own
Now go to terminal and run
gedit /etc/mod_switch.conf and write the following lines in it:
Please make sure you put the right entry. Default vendor and product can be obtained from
lsusb command. Target vendor, product and message content from the file I mentioned above. Save it and close the file.
Now open the terminal and run the following command:
sudo usb_modeswitch -c /etc/usb_modeswitch.conf