Nice output for exception of exceptions

In OCaml it's possible to let an exception carry another exception:

exception Example of exn

But when this exception is raised from another module, the output looks something like this:

Module.Example(_)

Any solution to this? What I want is of course

Module.Example(Not_found)

or similar.

I have this problem in OUnit, so it's not possible for me to solve it with a well-placed try ... with.