To those who are running Sforzando in standalone mode, not in a DAW: in what way did you customize it? jdg78 linked the free demo version of Velpro to SFZ to have a velocity editor. The description can be found in the thread "Santa Marta Fazioli F308 2.0 BETA".
I have plugged in a recording function with Savihost.
The how-to was posted a long time ago in the other piano forum for a Kontakt based instrument. The procedure works accordingly for Sforzando.