I g00gled for this and found no good answer but some good bits. And here is how they came together:
1. you need the usbserial and a recent copy of the option [GSM driver] modules loaded;
2. the reset sequence (via usb_modeswitch):
DisableSwitching=03. I connected via vwdial, this is the config file for it [it's Wind-specific]:
# Huawei E1691
[Dialer Defaults]I used Knoppix 6.4.4 to connect and it worked beautifully.
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init4 = AT+CGDCONT=1,"IP","broadband.windmobile.ca"
Modem Type = Analog Modem
Baud = 115200
New PPPD = yes
Modem = /dev/ttyUSB0
ISDN = 0
Phone = *99#
Password = gprs
Username = gprs
Mind you you need good signal (which can be a problem with Wind).
VMware/Windows note: if you run Linux in a VM and you assign the USB stick to it then when you use usb_modeswitch it will cause the stick to re-enumerate and kick some "Found New Hardware" dialogs in Windows. Ignore them (Cancel).