[Evolution] Backup Evolution Data .. only works for "On This Computer"?

[Joakim Tjernlund <joakim tjernlund transmode se>]

I trying to save all my Exchange mails(using EWS) to local disk and tried using
"Backup Evolution Data" but the resulting file is only a few KB's so obviously 
it didn't work.

So I figured I could use "Copy Folder to" each folder from Exchange account
to "On This Computer" but then I lost the "Received" date as Evo rewrites 
the date.

Any ideas? I am on evo 3.16.5

 Jocke