Schafter in TBOGT

Hey there, is there a reason why I can't mod the Schafter in TBOGT (the normal one, not the 2nd generation that Tony drives) ?

I installed a model by Spark IV and GTA Vehicle Installer, but in the game, while the handling of the car is of my mod, the model is still the stock Schafter. What could be the problem? Is the Schafter model loads from another vehicle.img?

Note that I already installed custom car mods for both the Schafter 2 and Schafter 3 (Second generation Schafter modded and normal version, respectively) before I did this. Could it be because the game doesn't recognize it?


edit: Already searched it, no topics about Schafter bug (?) here.