Resolution
Plesk provides ability to manage Acronis TrueImage Software by means of Plesk ATIS module in order to make partitions' backups using Plesk CP. The module can be installed using console autoinstaller or updater tool from Plesk CP. Or you can install 'psa-atis' package manually using your OS packet manager.
ATIS server itself should be installed manually, see installation guide. You can download it from http://www.swsoft.com/en/download/plesk/acronis/ or http://download1.swsoft.com/Acronis/.
There are special ATIS server builds that work with Plesk ATIS module and require Additional license key, it can be Light or Pro version, you can find more about it at the http://www.swsoft.com/en/buyonline/plesk8/addons/ and http://www.swsoft.com/en/products/plesk/acronis/.
The license should be uploaded via "Server->License Management->Additional License Keys->Upload Key".