Restore user mailbox when user & GW account deleted

All I have is dbcopy of the domain/postoffice

I could also restore user eDir object from backup (if that makes mailbox restore any easier?)

Only after user was deleted, some other users realized that in that user mailbox were some very important folders (that were shared)
It wasn't sudden unexpected error deletion. It was months in advance planned job termination, it is amazing that users do not do proper job handover!

But here I am, I need to restore the mailbox (and especially these folders with they content)

What would be the easiest way?

GW2012 SP1 on OES2 SP3

dbcopy backup exists on a remote Samba share on NAS

Thanks for any pointers