Backing up an external disk with Time Machine

[apostolosdt]

Recently I connected a 3TB Lacie to an MP 6,1 and I had the disk backed up with Time Machine. I did that in order to be able to recover various important folders kept on the external disk in case the latter fails. But then I found out that the disk's folders appear in Time Machine only when the external disk is present and connected. How then will I recover its contents if it fails and the computer doesn't "see" it?

What am I missing here?

 

[tensixturtle]

Can you try this in Finder?
[Backup Drive] --> "Backups.backupdb" --> [Computer Name] --> [Date of Backup] --> [Name of External Disk]

 

[apostolosdt]

Can you try this in Finder?
[Backup Drive] --> "Backups.backupdb" --> [Computer Name] --> [Date of Backup] --> [Name of External Disk]

Thank you very much! Yes, that's the way, good!