Fireplaces, Heating Stoves, Flues and Chimneys - TV Wall Mount above fireplace

I want to mount a large screen LCD above the fireplace, but the builders had framed it with 2x4's at the corners with metal studs in-between to support the drywall. I want to cut a section of the metal stud so that I can frame in a 2x8 the width of the fireplace, and ultimately use as the TV support.

http://img8.imageshack.us/img8/9484/fireplace01.th.jpg (http://img8.imageshack.us/my.php?image=fireplace01.jpg)http://img8.imageshack.us/img8/7042/fireplace03.th.jpg (http://img8.imageshack.us/my.php?image=fireplace03.jpg)http://img11.imageshack.us/img11/3908/fireplace04.th.jpg (http://img11.imageshack.us/my.php?image=fireplace04.jpg)http://img8.imageshack.us/img8/6192/fireplace02.th.jpg (http://img8.imageshack.us/my.php?image=fireplace02.jpg)

The only concern is that the distance to the flue from the front drywall is 6", so the stud would only be 4.5" away from the edge of the chimney. The paper face of the drywall is facing the chimney, so I'm leaning toward this approach. Is this okay? If not, any suggestions?

Set and attach wooden studs inside your metal studs in the area of the install. It will beef up the stud enough. From that you can lay in a couple of 2x8's laying flat for the attachment of the screen brace.

Easy enough. Thanks! (Harder to get 25 characters in a post ;))