for those that are on the way to migrate exchange mailboxes from one domain to another:
exmerge won't migrate the permissions on the calendar & co. Even if you keep the SID.
Let that bad friend(exmerge) for a new one : setperm !
That great tool will allow you to set permission on calendar, contact, inbox...
The readme say things, but it worked for me with this config:
-Windows XP last update
-Office 2003 last update with CDO
Just register the dll, and use an accound that have full access to all mailboxes (not domain admins!!!).
If you have an error about a bad picture, that's because your account isn't admin of the workstation.
The only bad side is the outlook security alert (Twice per box) asking you to allow setperm to play with him :)
You may think you are out of hell...just ask your users about their filtering rules...
download setperm here: http://www.amset.info/downloads/Setperm.zip