Hi @l.jakobs
We are sorry for making you wait so long to get our response.
As you may already know from our replies through the Alumio Support that we don’t support abstract properties yet. However, we have added it to our backlog for further discussion with the team.
There is a workaround for this issue by using HTTP Transformer instead of SOAP transformer. In order to generate the correct XML, you can map your JSON entity by following How to map with Serialize: XML.