Sorry for the late response to this. There is IBM Redbook title:
The Three Steps to Super.Human.Software:
Compare, Coexist, Migrate
From Microsoft Exchange to Lotus Domino
Part Two: Coexistence and Migration
I found it on page 96.
http://publib-b.boulder.ibm.com/Redbooks.nsf/9445fa5b416f6e32852569ae006bb65f/27ed0d41cf1d31ea8525679200699efa?OpenDocument&Highlight=0,Exchange
Rob, I realize by now you have determine this, but hopefully this might help someone else.