Mounting the camera in the GoPro box is a little trickier. The easiest solution was to 3d print a mount which fits snuggly inside the box and has a hole to mount the camera. The design is here http://bit.ly/2drxVC4.

The design has legs to stabilize the mount inside the box and keep the lens a fixed distance from the box surface.

Here is the final result with the camera and video balun inside the GoPro box.