@Tom Inglis and tomx: following are the steps I did to get the device working. I didn't create a wiki page because I couldn't find the right place and ubuntuguide.org doesn't let me edit. And maybe some day this bug will be fixed and getting the device to work will be easier :)

## Download the firmware and copy it to the right place
I have a ThinkPad T510, so I downloaded the driver from http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-72938 and installed it on Windows. Then I copied the files from c:\Programme\QUALCOMM\Images\Lenovo\6 and c:\Programme\QUALCOMM\Images\Lenovo\UMTS to /lib/firmware/gobi (you'll have to create that folder). Check http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c01738839&jumpid=reg_R1002_USEN to find out which folders are right for you

## Install the kernel patch and gobi_loader
Open a terminal
mkdir umts
cd umts
wget http://launchpadlibrarian.net/46353288/usb-wwan-2.6.32.diff
sudo apt-get install linux-source
tar xjf /usr/src/linux-source-2.6.32.tar.bz2
mkdir temp
cd ./linux-source-2.6.32
patch -p1 < ../usb-wwan-2.6.32.diff
cp /lib/modules/`uname -r`/build/.config ../temp
cp /lib/modules/`uname -r`/build/Module.symvers ../temp
cp /lib/modules/`uname -r`/build/Makefile .
make O=../temp outputmakefile
make O=../temp archprepare
make O=../temp prepare
make O=../temp modules SUBDIRS=scripts
make O=../temp modules SUBDIRS=drivers/usb/serial/
sudo cp ../temp/drivers/usb/serial/usb_wwan.ko /lib/modules/`uname -r`/kernel/drivers/usb/serial/
sudo cp ../temp/drivers/usb/serial/qcserial.ko /lib/modules/`uname -r`/kernel/drivers/usb/serial/
sudo cp ../temp/drivers/usb/serial/option.ko /lib/modules/`uname -r`/kernel/drivers/usb/serial/
sudo /sbin/depmod -a
cd ..
wget http://www.codon.org.uk/~mjg59/gobi_loader/download/gobi_loader-0.5.tar.gz
tar -xzf gobi_loader-0.5.tar.gz 
cd gobi_loader-0.5/
make
sudo make install
cd ../..
rm -r umts

Now reboot the system and the NetworkManager applet should have an "activate mobile broadband" option
lsusb shows "Bus 002 Device 004: ID 05c6:9205 Qualcomm, Inc."
In /var/log/messages I see
Jun  2 09:08:04 tptfeubu kernel: [    4.324342] USB Serial support registered for Qualcomm USB modem
Jun  2 09:08:04 tptfeubu kernel: [    4.324378] qcserial 2-1.4:1.1: Qualcomm USB modem converter detected
Jun  2 09:08:04 tptfeubu kernel: [    4.327814] ip_tables: (C) 2000-2006 Netfilter Core Team
Jun  2 09:08:04 tptfeubu kernel: [    4.328086] usb 2-1.4: Qualcomm USB modem converter now attached to ttyUSB0
Jun  2 09:08:04 tptfeubu kernel: [    4.328105] usbcore: registered new interface driver qcserial
and later
Jun  2 09:08:15 tptfeubu kernel: [   14.546188] usb 2-1.4: USB disconnect, address 3
Jun  2 09:08:15 tptfeubu kernel: [   14.546406] qcserial ttyUSB0: Qualcomm USB modem converter now disconnected from ttyUSB0
Jun  2 09:08:15 tptfeubu kernel: [   14.546414] qcserial 2-1.4:1.1: device disconnected
Jun  2 09:08:15 tptfeubu kernel: [   14.777742] usb 2-1.4: new high speed USB device using ehci_hcd and address 4
Jun  2 09:08:15 tptfeubu kernel: [   14.897398] usb 2-1.4: configuration #1 chosen from 1 choice
Jun  2 09:08:15 tptfeubu kernel: [   14.901479] qcserial 2-1.4:1.2: Qualcomm USB modem converter detected
Jun  2 09:08:15 tptfeubu kernel: [   14.901572] usb 2-1.4: Qualcomm USB modem converter now attached to ttyUSB1