Really the easiest thing to do is to go to the Vault Admin Console and right click "Archives" and select "Export Archive", you can then export it to a PST file or to the original mailbox etc
As for the user, theres not much you can really do to help them.
You can set up "Restore to PST" in the the Browser Search, however the caveats are that you have to find the items, add them to a basket, and then export to a PST , but the PST will be local on the EV Server so you would need to set up a location for them to be able to access their PST files. oh, and you need to edit the webapp.ini to enable that feature.
Other methods might be to enable them for Vault Cache and Virtual Vault and then once it has fully downloaded and completed, you can then copy the items from the Virtual Vault to a PST file.
Virtual Vault itself though is meant for offline use and looks exactly like a connected PST file within outlook, so if your user just needs the archive in a PST file for offline use, then this maybe the best solution for you,
https://www.linkedin.com/in/alex-allen-turl-07370146
