Geek_Mika - that is not currently possible, although that would be a great feature to add to our feature set.
Currently OMM cannot add any server to OpenManage Essentials. It can only view something that is added.
If you add an iDRAC to OMM (whether through Quick Sync or through the iDRAC web interface), it can be managed from the mobile device but not OpenManage Essentials. You'd have to separately discover that iDRAC/Server using OpenManage Essentials in order to manage it using OpenManage Essentials.