Need to assign the NT authority self permission to every mailbox in the store on exchange 2007

I need an exchange management shell commmand syntax to run or tell me where in ADSIEDIT how to assign the self permisison to every mailbox in the information store on 2007.  I am moving mailboxes from 2003 to 2007 and some of them come over with the self permission in tact but some of them do not and I am having to go back and manuallly add the NT authority self full access permissions before the user can open the mailbox in outlook.  I have been searching the web in vain trying to figure out where I set this or what command syntax to use in the shell on the 2007 information store.  

Will this command do it??

Get-Mailbox | Add-MailboxPermission -user self -AccessRights FullAccess

I found this for specific usernames to add the full access permission.. but unsure if you can plug the username self in there or not..


thanks,