Actually, because of the server-side authentication requirement, you can't
back up network shares without logging in.  As far as persistent, your
network mappings are actually re-established each time you log in, so
services don't have access to them.  Instead of a prescheduled command,
because there might be mapping inheritance issues across shells, you might
try, for your backup, a script/cmd job with....

net use x: \\servername\share mypassword /user:mydomain\myaccount
dsmc inc x:

Personally, security on Windows platforms gives me the heebie jeebies, so I
don't like leaving my password in text files.  I experimented, and I had
some success creating a local account with the same name and password as my
domain account.  Under that local account, I then used:

net use x: \\servername\share /user:mydomain\myaccount

and it connected fine.  My guess is that it sent the local account's current
password to try to log into the domain account.  I don't like this behavior,
but I had hoped that would happen seeing as how this is a Microsoft OS.  I
didn't go the extra step to confirm that's what was happening, but it might
be worth your experimentation.

I hope this helps.

Alex Paschal  (MCSE, btw)
Storage Administrator
Freightliner, LLC
(503) 745-6850 phone/vmail