And this link helped me solve the last issue I got.
… and ofcourse, a few minutes after posting my question I find a solution. For those who is trying the same thing, this link helped me out.
Next thing for me to do is making the titles of the new columns clickable so that the overview can be ordered accordingly.
Hmz, sorry for the spam, but after some rethinking, my earlier reply did not in fact solve my problem. I do need to use the custom post type in my flexible content field…
So back to my initial question; how do I get custom post type data like title, content and excerpt through a flexible content field?
I’ve seem to fixed the issue by replacing the post object (custom post type) with a normal repeater.
I think it’s still possible to use post objects in combination with the flexible content field, but for now my problem has been solved.