Hello Anka,
Main question: Does the backup software clear the Archive Attribute from the stored files
On the Vault Store Partiton, note what the actual location is. Browse to that location (using Windows Explorer). Right click an item which should have been backed up, look at the properties. You should at the bottom of the properties see no checkmark in Archive, also look at Details tab, line Attributes. That should not have an A listed.
If you started using a new partition, is it included in the backup? Does the backup succeed? Is it configured to clear the archive attribute? Are the other Vault Store PArtitions configured the same? Do they show archive attribute?
If you want to 'test' it is indeed the arcvhive attribute not being cleared:
set backup mode on the vault store. run backup. clear backup mode. You should see storagefilewatch process in taskmanager. After a bit, alert should be gone. If it is not, then set backup mode again, open command prompt (as admin), make sure you can access the share from prompt. browse into a folder you know has recent items. run attrib -a *.* Clear backup mode.
Verify items go down. If the last one proves to work,then you need to check your backup settings, as then the archive attribute is not cleared.