How to separate LCD from metal casing/back?

This is for a HTC EVO DESIGN 4G cell phone. Has anyone removed the LCD from the attached metal back? I need to do this in order to replace the cracked glass digitizer. The problem for the HTC EVO DESIGN phone is that there is a cable that is attached to the glass lens and it need to be connected to the motherboard by running it between the LCD and its metal back. I am not sure how much pressure/ heat I should apply. I am afraid I will break something I don't see or the LCD itself. I am nearly there, and really need help. Can anyone suggest anything? I cannot find a single document for the DESIGN on the web.