After setting up mail and calendar synchronization with our Exchange server (Exchange 2010) and the built-in app, I cannot edit the entries in the Exchange calendar. Adding new entries works fine.
Comment #15 of a Google code issue shows an important hint. It works when the "primary E-mail address" is used when connecting to the account.
Could there be other reasons? How do I find the primary E-mail address (short of asking the system administrator)?