MacOS 10.7 (Lion) was publicly released on July 20, 2011.
This update has some new requirements in order to use AFP (Apple File Protocol) and ATM (Apple Time Machine). BlackArmor NAS units require updated firmware to be compatible.
The error you may experience may be similar to:
The version of the server you are trying to connect to is not supported. Please contact your system administrator to resolve the problem.
The network backup disk does not support the required AFP features. Open Time Machine preferences to select a different backup disk.
Please see our downloads page to update your BlackArmor NAS unit's firmware.
For troubleshooting Apple Time Machine with BlackArmor NAS, please see Document ID: 218011.