Can't get Switch item to send via MQTT values different than ON or OFF

Hi, I have something like this (although I already went through many revisions, none of seem to be working) for my item and sitemap definition:

Switch Diode2 "Diode light1" <siren> {mqtt=">MQTT:openhab/in:command:*:1"}

sitemap demo label=“My home automation” {
Frame label=“Switch1” {
Switch item=Diode2 mappings=[0=“OFF!”, ON=“ON!”] icon=“light”

After having this defined, I do mosquitto_sub -t openhab/out/Diode2/command. When I push “ON!” button, mosquitto receives “ON” signal. When I push “OFF!” button, nothing is happening (if I change the mapping for this button from 0 to “OFF”, mosquitto will start receiving “OFF” signal).

How do I get this thing to send 0/1 values, instead of ON/OFF?

A switch item is only able to get three states: ON,OFF,null (and null is no valid state either…)
So, to send 0 and ON, use a string item and don’t forget to change the mappings to strings.