You can't, Mendix does not generate code from your model but executes the model itself. Have a look at http://www.theenterprisearchitect.eu/archive/2010/06/28/model-driven-development-code-generation-or-model-interpretation if you're interested in the why's.
Don't think that's possible. You could trace the sql queries which are executed in a microflow, but not the specific code used by the mendix business server to run such a microflow.