For anyone else seeking this answer like me....
I just figured it out while preparing for a TDM repair on my own surface. There is absolutely no inforation on this whatsoever. BUT, i figured it out. I think. What i did was install the surface diagnostic toolkit, open the app, on the left side click the settings icon, then change the mode from "normal" to "technician" and then restart the app, there is now a drop down that gives you an option for repair setup and validation. There are now options for TDM repair setup, calibration and validation.