thanks for your answer.
I added in uniconfig.h in void uiInitKeys():
UI_KEYS_INIT_BUTTON_LOW(48);
UI_KEYS_INIT_CLICKENCODER_LOW(50,52);
under void uiCheckKeys(uint16_t &action) i added:
UI_KEYS_BUTTON_LOW(48,UI_ACTION_Z_BABYSTEPS);
is this the right direction im going?