I use the Overkiz integration to use the shutters from Ha. This works great. My question now is whether the Somfy Smoove 1 IO radio senders can also be set up as an entity in HA? This would allow me to use these buttons in HA for various purposes as well. I tried to set them up in the Tahoma app, but apparently only the roller shutters can be integrated there. I would be grateful for any tips.
If you cannot control this via the TaHoma app, you can probably not control it via HA as well. If you download your Overkiz diagnostics file from HomeAssistant, you could check the JSON and see if your device is present.
i can confirm this error for an Smoove origin RS100 io (#1811717): in the Tahoma web application i can include the button (see ‘Systemeinstellungen’) and assign an action to the buttons (see ‘Konfigurieren’).
In HA I cannot locate this device / entity 
who can support here?
You can create an issue on GitHub and include your diagnostics log.