Data is migrated from the old archive to the new archive. Archive permissions are synchronized as well.

This is from Page 4 on:

ftp://ftp.entsupport.symantec.com/pub/support/products/Exchange_Mailbox_Archiving_Unit/351473.pdf

Cheers

Page 75 of the Admin guide describes the process. I can imagine that if the user is not yet provisioned, or synced, the permissions are not set (yet).

What happens if you sync the user? Do permissions get set?

Thanks all for your replies (Damon, Michel and Gertjan ;)

I personally feel that the documentation that MichelZ points to and the Admin Guide are incorrect and need updarting to reflect the scenario when moving between directories. 

Damon is right in so far as his statement, and so I'll award him the solution for this, but the documentation had confused me no-end;

"However, if you enable the user in the other directory for archiving first, you can specify that user's archive as the location to migrate the old archive to. I suspect that will make things a lot easier for you."

I Disabled the user at source first, then provisioned the other side, and moved to the existing archive (all went well).  I stupidly thought that moving to a new archive would copy permissions too as per doc 351473 :(

Oh well, learning as I go...

Just noticed that if you move to an existing archive (as above), you MUST allow for the archiving task to run (either manual or scheduled) in order for shortcut processing to take place, otherwise you're stuck at "Waiting for shorcut update" in the Move Archive Status.  Really dumb if you don't use shortcuts (as we have virtual vault)...

So, either way, the Move Archive process requires alot of manual intervention and/or waiting around for scheduled tasks to complete, which is not ideal for me.