This allows our Support agent to reply with the Email Composer, and the original EmailMessage appears in the Email Thread.
I would like to achieve the same functionality with other originated cases, such as 'Web' (via Web-To-Case), Portal, etc. These cases are not creating a 'feed item', and only sets the 'Case Description' field:
I know that I can use the 'Case Description' as a merge field with an Email Template when replying, but I wanted to understand if there is a better solution, which might involve creating the 'feed item' (Trigger perhaps?).