I'm trying to move a whole server with Plesk 7 to a new box with Plesk 7 Reloaded.

Besides changing DNS for domains, could anyone tell me if I can move the data directories (/home/httpd/vhosts/, mysql data files, qmail mailboxes etc) to the new server without having any data loss ?

Is it possible to use Backup/Restore utilities from Plesk 7 and move the dump file to the new server and restore there?

It's a must to have them all moved to the new server, because this old server will be shut down in about a week from now.

Plesk 7.1 Reloaded comes with this great new tool, called a "Migration Manager". It makes all this a snap for you. All you do is go into it on Reloaded, select "PLesk 5.x, 6.x, 7.x" from the dropdown, and enter in the root login for SSH on the remote server (the one you are migrating from).
It will automatically upload the migration tools to the old server, grab all the data you want, and let you pick and chose which gets migrated.
It does databases, mailboxes, websites, clients, logins... I notice the only thing it does NOT handle is mailing lists (mine refused to migrate, so I had to do these manually).
I moved about 12GB of sites in just under 9 hours, so you should have more than enough time with a week.
If you want to read up more on the migration manager, head over to the Plesk forum at http://forum.sw-soft.com