Dell WiFi BCM4312 only shows if boot with HW switch on

[joelgsf]

I have a Dell Vostro 1510 which I upgraded recently with Ubuntu 12.04. Since then, WiFi connections are only enabled if I boot the machine with the hardware switch in the "on" position. If I boot with the switch off there is no way to turn the Wifi on, even if I set the switch to on.
Can we solve this problem?
Thanks.