Hi Christian,
thank you for your answer. I did check the documentation and did it like that.
<callActivity id="CallActivity_1" name="Funktionskontrolle" calledElement="Funktionskontrolle">
<extensionElements>
<camunda:in variables="all"/>
<camunda:out variables="all"/>
</extensionElements>
But still it seems that it won't override. If I use an expanded subprocess instead of a call activity it works. I am using 7.2.0-alpha5 with tomcat btw.
Regards,
Dennis