Comment 4 for bug 492772

I'm runnig Ubuntu Karmic too, so I have the same problem, but found an ugly workaround:

First i use usb_modeswitch as stated in many places:

> sudo usb_modeswitch -v0x0fce -p0xd0e1 -O 1

Then I try to connect using wvdial, it doesn't work, but somehow it seems to initialize the MD400 (a blue lamp starts blinking)

> wvdial

I use the following /etc/wvdial.conf :
---START---
[Dialer Defaults]
Init1 = ATX3
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init3 = AT+CFUN=6
Init4 = AT+CGDCONT=1,"ip","internet.sonofon"
Phone = *99#
Modem Type = USB Modem
Baud = 460800
New PPPD = yes
Modem = /dev/ttyACM0
ISDN = 0
Password = ''
Username = ''
---END---

Note: Modem = /dev/ttyACM0 have to be changed to whatever your device is ttyACM1, ttyACM2,... or even ttyUSB0,... I don't what other part of the file might be important, it just worked for me.

After that the network manager can connect using the default settings.

Note: you have to run the two lines above every time you plug in the stick or restart the system.

As mentioned, I think the problem occurs somewhere in the initialization of the modem, but cant say where precisely, as this fix was more luck then something else...

System: EEE Pc 1000, Xubuntu Karmic, Sony Ericsson MD400