Ebusd setup in HASS

Hi all,
I am struggling now since a couple of weeks and would like to ask for your support.
I run HA on and RPI and have a Vaillant ecoTec heating, connected with an ebusd device / mqtt. So far so good. I receive most values from the heating.
However, I do not manage to configure the ebusd add-on via my own configuration file (mqtt-hassio.cfg). The add on seems to have no access to the files I offer. I tried files in /homeassistant, /config, /etc/ebusd, /addon_configs/ebusd. I always receive “file not found” errors in the protocol.
Would you have any hints how I can manage to grant access rights to the add-on? As mentioned, I use HASS on an RPI and have no clue, how I can access the add-on docker. Probably an easy one for someone who knows what he/she is doing :wink:
Thank you upfront!
Marc