2003 X5 battery drain because clock/radio comes on when temps go below 40 degrees

I have a 2003 BMW X5. I am having a serious problem with the cold weather. When the temp drops below 30 degrees, the clock/radio comes on by itself (car is parked in my garage, no key in ignition. This drains my battery, and has left me stranded with two little kids. I have a brand new battery and alternator in the last month. Have even pulled fuse for the onboard computer, and the clock is still coming on. What causes this? How can it be fixed? I have read there was a recall for this probelm, is that true?