Need help USB modem

[Roger]

I have the laptop here at home for the weekend and still have trouble 
getting the Sierra aircard 312U modem to work.

Following instruction on the Sierra site: 
http://www.sierrawireless.com/Support/SupportCenter.aspx

-Have installed the kernel module provided by Sierra for the latest kernel.
-modinfo sierra shows the correct version

-modinfo-sierra_net shows that ist's installed in 
/lib/modules/x/x/x/x/x/x/sierra_net.ko

-ls /dev/ttyUSB* shows /dev/ttyUSB0 to3

ifconfig does not show the usb,
it only has etho, lo and wlan0 so now I'm stuck as to where to go from here.

Can someone please advise
thanks in advance
Roger