Tasmota does not find devices

Hi,
I have both the MQTT Client app and the tasmota app installed.
I also created a new user on my (external) mosquitto broker, entered it into the settings page and verified both in homey and the broker that the client is in fact connected.
I then tried to detect my tasmota devices using the add device screen however it never finds any.

I suspect the reason for it is that I use a custom tasmota topic, however I couldn’t find any place to set that in homey.
My fulltopic setting in all tasmota devices is tasmota/%topic%/%prefix%, how can I configure that in homey ?

The app’s forum topic says this about the MQTT topics format:

It’s best to read this Tasmota app thread, and post additional questions in there as well (reaching developer(s) ánd fellow app users):

App forum topics are usually mentioned at the app page @ homey.app