I would try
http://xmlgrid.net/Basically, almost anything can be integrated with OpenText (it is only a balance between requirement and time).
If it is as simply as
1. Clicking on something that loads up a page with browser friendly HTML/XML/Text editor
2. Onload, use RQL to get content from specific content element, load the content into editor
3. User plays around with the content
4. Onclick OK/Save, save the content back to content element via RQL.
I have done something with
http://remiya.com/htmlbox/index.php/9/demo/full-featured-demo.html before.