Updated 6th October 2013: With the removal of the MCM classes from Microsoft Learning’s provision of training and certification, I have posted this video content on my own blog at http://www.c7solutions.com/2013/10/the-exchange-server-header-firewall-mcm/
Fame at last! Well not really, but here (http://blogs.technet.com/b/themasterblog/archive/2010/12/28/mcm-exchange-video-preview.aspx) is a video introducing the MCM Exchange class posted on the MCM Blog. The video is a 30 minute segment from the class without the interaction amongst the students that the class always has, and the reason for this lack of interaction is that it was recorded in the front room of my house.
Typically this content (the Header Firewall and Connector Permissions) could take one hour or more to cover when you include specific examples, a lab and all the different things to be aware of with regard to the subject.