Libraesva ESG, from version 4.7, has a complete mail continuity feature.
You can access this feature from the message details.
Allowed actions are:
- Load message images
- Release the message
- Add a whitelist
- Add a blacklist
You can fill every field of your new message like in a e-mail client.
You will also be able to compose a new message, clicking on the green pencil button, as shown in the image below.