want to erase all the Prefered Networks ?

Have a course with 130 students using 130 laptops every 2 months.

I have to find a way at user logon to change the Preferred Network at the
verry first logon of a user so that I can load balance half of them on a SSID
and the other half on another SSID.

So far I'm using the tool provided by the Wireless connection Wizard
"SetupSNK.exe" when you dump the Wireless config on a USB key to create the
Preferred Networks at logon. What I can't find is how to ease a Preferred
Network by means of script??? either one or all of them???

Also, I've noticed that the order in wich the Preferred Network are showed
is not always the order it will try to connect first.

This is for XP PRO SP2 Laptops.

Pete