Help parameters

Hi,

I'm playing Moonlight's Sonata (Beethoven) on PTQ D4 and Blüthner (Concert record AB) and I'm somehow sure I can get a better sound for it.

I basically noticed that the left hand notes in this piece don't last as long as desired (not to confuse with reverb), I keep the keys pressed for the whole bar but the sound fades away too quickly. I tried increasing the impedance and it halfwise improved the sound, but another problem came out, as I'm pressing the damper pedal for the whole bar as well, all the played notes (even the right hand which isn't keeping keys  pressed) last for ever...

Question: Is there any way to increase the length of the pressed keys keeping the damper effect as it was originally? I guess I'll have to fiddle around with more than a single parameter, do you know which of them at least?

EDIT: Have just figured out how to increase the impedance only on the lower notes (note edit section) by turning up the lower node of the linear horizontal curve (0º). Wonder if there's another way for non pro users.

Thanks in forehand,
David