box2d as my own shape?

Hi!

Im using box2d and want to figure out how to draw my own shape (to be able to get the shape in the end from a kinectcam) instead of getting this cubes circle and straight lines.
http://charles.bascou.free.fr/box2d/

i wounder if there is something similliar as the "dynamicmesh" shape that is possible to use in jit.phys.body.

I already tried this with jit.phys.body but problem with jit.phys.body is that I cannot get this 100% solid and rigid. sometimes bouncing objects are going straight through the dynamic mesh instead of bouncing no matter how I change the different settings.

So. now i want to use the box2d instead.

any way of getting a dynamic mesh and my own custom shape within box2d??

thanks