My mother using an external Web-cam with a Microphone. The PC doesn’t recognise the Microphone automatically. So I always have to activate it myself in the Audio Settings as Audio Input device after a restart. How can I avoid this and set it as default Microphone.
This PC doesn't have another Webcam or Mic. And the Web-cam is always pluged in.

Ubuntu 12.04 beta with latest updates (I also had this problems with 10.04)
Logitech, Inc. Web-cam B500