I have just stumbled across a new fsx.cfg setting ForceVCShadowMap. Jesus Altuve had mentioned that this setting existed in the past but with no explanation of what it might do.
In DX9 mode it does nothing, which I why I guess it was forgotten.
However in DX10 mode it seems to enable (force) VC cockpits for all aircraft regardless of the setting in the VC Model file.
To enable this locate the [Display] section and add
With this setting enabled there is no longer any need to use DX10Toolbox to turn the VC Shadows on in the model xml file.
If you are using DX10SceneryFixer there is another bonus to this new setting.
If you create a profile with
Legacy Aircraft Self Shadow ticked in the Legacy Dialog
HD Shadows unticked in the Shadow Dialog
Force VC Walls ticked
Then with luck you should find that you have VC Shadows in your legacy FS9 aircraft as in this Ilyushin Il-18
I shall see if I can enable HD Shadows for these aircraft in the next release.