I have an external speaker system connected to my MBP when I'm at work. However, if I plug it in before waking the computer, the computer seems to ignore the fact that it is plugged in and just uses the built in speakers. I have to unplug and then replug the phono jack for it to start working. Is there any way to overcome this problem? It is obviously a software issue, so I'm wondering if there is a preferences setting for it.