I was hoping for some Export-Mailbox -PSTFolderPath functionality for mailboxes in a database in a recovery storage group but what I ended up doing was:
get-mailboxdatabase -identity “ServerName\Recovery Storage Group\Mailbox Database” | Add-ADPermission -user “domain\adminusername” -ExtendedRights Receive-As
Then using ExMerge on an Exchange 2003 box to export the mailboxes to PST format.
The following Powershell may be a little useful when using Recovery Storage Groups:
Get-MailboxStatistics -Database “e2k7server\Recovery Storage Group\Mailbox Database”|Where {$_.DisplayName -eq “A N Other”} | fl
I didn’t get as far as getting the id and trying the Export-Mailbox command as I ran out of time and had to opt for ExMerge but I would say it should be possible.
http://all-data-recovery.blogspot.com/2008/10/splitting-pst-became-easy.html