For our Helikite (http://www.allsopp.co.uk/) the stock camera mount wasn't doing the trick for what we needed. We decided to build a picavet to hang underneath. With some direction from Charles Benton's website (http://arch.ced.berkeley.edu/kap/equip/picavet.html) we constructed the cradle from some 1/4" basswood, a few small screw eyes, and a bent metal coat hanger to attach the camera to the cross. The whole thing was attached to the balloon with two Prusik knot loops (the pink string on the bottom photo).
Below are the instructions for constructing a basic pole camera with
off the shelf parts. You’ll need something to trigger the camera while
it’s up in the air. I use the remote that came with my DSLR or an IR
intervelometer, you could use a wired trigger if you can make one with a
long enough cord.All of the materials for this project can be found at most home improvement stores.