Because SMS failed to see the difference? Or, perhaps, because the clutch is broken and you can use the H-shifter like a dog-box, they felt no need to identify the seq stick cars as such.
I merely put two large rubber bands around my stick so it only goes up and back through 3-4 gears, then set my upshift to match 3d gear and downshift to match 4th gear. Then I get the whole late-90's, early 00's racing experience.
Remember to lift-blip on some of the older cars with the seq shifter to maintain the immersion.