Further to this discussion, I have created a new block in order to display teacher's comments on Lesson essays (and grade) to students. This block will be available from the Modules and plugins download page, at this address (as soon as it has been approved by a moderator). If you are in a hurry to test it, here are the github repository address for a) the project and b) the download files.
At the moment the only version available is for Moodle 2.0. If there is sufficient demand I will adapt it for Moodle 1.9. Language files available for English and French. Translations for other languages are welcome: please send them to my email address (see my profile).
Please test and report any problems in this Lesson module discussion.
PS. Attached screenshots.