Comment 373 for bug 446146

@Jose:
After some further investigation, I now have a working E1762-Modem using kernel 2.6.31-16-server (Karmic).

This seems to work without using the quirks-parameter for me.
Maybe udev calls usb_modeswitch early enough to be able to switch the device into proper mode, but I'm not sure about this.

I performed the following steps:

1.) Add some modem specific settings to /etc/usb_modeswitch.conf (Install the package usb_modeswitch before, if not already done):

#HUAWEI E1762
DefaultVendor= 0x12d1
DefaultProduct= 0x1446
TargetVendor= 0x12d1
TargetProduct= 0x140c
MessageContent="55534243000000000000000000000011060000000000000000000000000000"
CheckSuccess=5

2.) Create a file /etc/udev/rules.d/15-huawei-e1762.rules with the following content:

SUBSYSTEM="usb"
SYSFS{idProduct}=="1446",
SYSFS{idVendor}=="12d1",
RUN+="/usr/sbin/usb_modeswitch"

-----------

These two steps made the modem basically working for me, and you should get something like the following in your kernel log after restarting udev and plugging in your Huawei stick, if it works for you, too:

kernel: [ 78.175152] USB Serial support registered for GSM modem (1-port)
kernel: [ 78.175198] option 1-1.4:1.0: GSM modem (1-port) converter detected
kernel: [ 78.175272] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB0
kernel: [ 78.175279] option 1-1.4:1.1: GSM modem (1-port) converter detected
kernel: [ 78.175319] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB1
kernel: [ 78.175326] option 1-1.4:1.2: GSM modem (1-port) converter detected

Then I got another problem with the modemmanger resulting in the following looping messages (/var/log/daemon.log):

modem-manager: (Huawei): (ttyUSB1) deferring support check
modem-manager: (ttyUSB2): re-checking support...
modem-manager: (Huawei): (ttyUSB2) deferring support check
modem-manager: (ttyUSB3): re-checking support...
modem-manager: (Huawei): (ttyUSB3) deferring support check
...

This seems to be caused by a bug reported here:
https://bugs.launchpad.net/ubuntu/+source/network-manager-applet/+bug/410634

The solution was to use the network-manager and modemmanager packages build from trunk:
https://edge.launchpad.net/~network-manager/+archive/trunk

-----------

Now I was able to use the stick in the gnome network-manager to connect to Vodafone (Germany).

The last issue I had was the fact, that I had to define the DNS servers myself in the network-manager, because the resolv.conf file was not updated (they work for me with the Bildmobil Speedstick):

139.7.30.125, 139.7.30.126

I hope this helps.