GTA Episodes f. Liberty City: Cannot save control modification...

Although I am a rpg gamer at heart, I really loved GTA IV and played it till the final mission.

So i bought the expansion pack "episodes from liberty city", however i can change the control scheme (I hate playing with WASD, I usually use the arrow keys), however I cannot save my modified control scheme......

Has anyone a hint how i am ablte to save my modified control scheme ???

Thanks in advance,
L.