Lars -
The method is LabVIEWAdapter.ReserveLoadedVIsForExec. The specific adapter class are defined in a secondary type library which you can access in the type library named "NI TestStand Adapter API" Once you get a reference to the adapter using "Engine.GetAdapterByKeyName", just use the LabVIEW Adapter class in the second type library on that reference.
Scott Richardson
https://testeract.com