Sorry I don't have an answer but I would love to be able to do this too.
I also tried in the past to get this functionality but got nowhere due to the precompiled pyc files.
How do I output the thermal conductivity of a heat conduction model? Why can't I see it in the list of available output variables? I just want to plot the contours on a surface in a similar manner to how you would view a temperature contour plot.
