Found the solution tanks to watou user in OpenHab Forum.
Switch node2_sw2 "sw2 send + recieve example" (node2,all) {mqtt=">[mysensor:MyMQTT/21/2/V_LIGHT:command:OFF:0],>[mysensor:MyMQTT/21/2/V_LIGHT:command:ON:1],<[mysensor:MyMQTT/21/2/V_LIGHT:state:MAP(1on0off.map)]"}
The secret is in the :state: declaration on the MAP!
Thank you all