Sorry for my late response.
Unfortunately your suggestion didn´t fix the problem and it remains as described above: Connecting to MC works flawless, the custom template with editable areas can be selcted and worked on. Upon saving the new campaign doesn´t show up in the campaigns list.
The campaigns list itself seems to work, as camapsing created using “Create Campaign by Designing Template” show up just fine,
What else could we check / do in order to get this working (having editable Areas in MC-Templates within WP was the main reason this plugin suited our specific needs)?
Thanks in advance.