Since they can cancel inertia inside the ship, maybe they can cancel it outside, as well? Perhaps the inertial damping fields can be extended to affect the entire ship's mass and affect it, accordingly.
So they just have the Impulse Drive stop "pushing" the ship and then cancel the vessel's inertia to the point it "stops" (matches the velocity).
you win the prize, That was my solution as well. It's pointless looking at the drive components of a starship for a way to stop a vessel.
The IDF is a perfect way to slow and stop a ship. Action and reaction, simple physics.