I have been having issues with the BCM4322 wireless card on my macbook pro under ubuntu. As it turns out after some digging  the BCM4322 driver only supports the 'Rest of World' locale which does not include wireless channels 12 & 13. You can test this by trying:

sudo iwlist eth2 channel

Which on the macbook pro returns:

eth2      20 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Channel 36 : 5.18 GHz
          Channel 40 : 5.2 GHz
          Channel 44 : 5.22 GHz
          Channel 48 : 5.24 GHz
          Channel 149 : 5.745 GHz
          Channel 153 : 5.765 GHz
          Channel 157 : 5.785 GHz
          Channel 161 : 5.805 GHz
          Channel 165 : 5.825 GHz
          Current Channel:1

As you can see, no channels 12 & 13. Since my router had been set to 13 (it was less popular in my area) this resulted in no wireless for ubuntu. After a quick change to the channel setting on the router, ubuntu can see my wireless network. To find a channel which is not too crowded try using nm-tool or perhaps:

sudo iwlist eth2 scan | grep Channel