Qsynth connection

I use Musescore under Ubuntu
ALSA output works great, with realtime etc... However I'd like to use sequencer features as reverb ecc... more professional as qsynth or timidity. Obviously I pass by jack.
What I've already done:
1. check "Use JACK MIDI output " in I/O preferences of Musescore
2. From jack - section "midi" i find musescore as output and qsynth as input, allright.
I correctly hear sounds but just with piano path, because qsynth has every channel setted on piano, as attached snapshot.

By the way "synthesizer" from menu "tools" is disabled (obvious, I don't use internal synthesizer).
Shall I set EVERY TIME map channels->instruments in qsynth, depending on songs?
Can't I use the same method (maybe with timidity) and set FROM Musescore instrument I want to play that part??

Thanks a lot.