Q: macbook pro hmdi - audio not showing in preferences - any help?

Is anyone else having trouble with audio through the mini display port ?  I have an adaptor that supports audio and my macbook is mid 2010 and supposedly will transport audio through the mini port but sound preferences does not recognize the port as an output -  the video works fine.  Also, does anyone else have trouble getting through to a real person in real time in apple support - this is maddening.