Hopefully you are backing things up. Otherwise your not gonna be able to pull it out of thin air.
I'm now setting up a virtual server, same name and everything.
I'll load the mailstore into that virtual server, do a restore and make a PST-file...
A little bit of work, but don't seem to have any other option since SBS2003 can't handle 2 stores 
I'm now using Enterprise in the virtual enviroment
An old school-licence, but hell... if it works 
hello
the mail box can be recovered easliy if you are using exchange server 2003 which provide the featute the recovery storage group.
1.create a recovery storage group.if it is already there then its ok.
2.just the add the storage group or store where thr users mailbox reside.
3.mount the recovery storage group(RSG) it will create new restre database and checkpoint file
4.now open NTbackup -restore mailbox store and choose your information store backup of that store. the restore process will automatically goes to recovery storage group.
5. when the restore complete just take the sesired mailbox bac kup by exmerge.
6. give the exmerge to users or just merge the mail to current users mailbox.
regards