Cant set REgisters from MQTT

[chrzimmer]

Hello and congrats to this really useful piece of software. It is exactly what i was looking for: quick setup with docker and bridgning of Modbus and MQTT.
Unfortunately I run into problems when I try to set registers via MQTT.

My setup: on machine A I already had a eclipse-mosquitto container running. On this machine I installed mopoll via docker. On the remote machin B I installed modsim also via docker.

So far everything is running good after I explicitly configure MQTT protocol 5.0. On my Windows desktop I have a MQTT client running where i can see that the values of modsim are written to mosquitto.

But when I publisch
{"object_type": "holding_register", "address": 40001, "value": 12 }
to
modpoll/modsim01/set
I would expect that with the next reading of modpoll I read "12" from register "holding_reg02", but i still read "2" like before. So it looks like nothing has changed.

Can please someone point me to what I am doing wrong ?
Thanks for your time.