How do I remove the starter rope on my Troy Bilt TB70SS weed trimmer?

I have a Troy Bilt TB70SS weed trimmer and the starter rope broke.

I took off the clutch housing and theres this steel plate that im having trouble with (I believe the steel plate could be the clutch). There is a screw inside the steel plate BUT everytime I turn the screw with a screwdriver, the engine turns with it. I even stuck another screwdriver inside the engine to stop it from turning, BUT when I do this... the screw wont loosen... its like stuck or really tight.

Am I doing it the right way or what? Is there something that im doing wrong?