I have also struggled for sometime with the same issue. You can follow the steps in this blog post to get it working: https://medium.com/rewrite-tech/how-to-create-adobe-campaign-standard-acs-forms-in-aem-a31ffb1d81de

Try using scriptlets like the ones that you find in Content Blocks in ACS.

Hi,Not sure if you already solved it or not but try something like <%= target %> , it should work.

Hi,is it really working with all these steps or you did something else too? I was not able to get the adobe campaign button in dialog working though i have tried all the mentioned steps. In browser console, i am getting window.top.ContextHub as undefined.

Tried this? Accessing an external database