EDID - Disable HDMI Audio

Hello,

I have an early 2009 MacBook Pro that is connected to an external display using Mini-Display Port to HDMI. (HDMI audio is not supported on this model).To enable audio I must use an analog audio cable. The external display will only accept analog if there is no HDMI audio present. I found a solution for Windows that disables audio capability on the external display by using a registry EDID override. However, I'm not certain how to go about this process on Mac. I would be incredibly grateful for any suggestions.

Thanks.