I haven't used those commands, just to say upfront.
But when i opened the manual, HP suggested that
pax should be used instead for archiving purpose.
With pax, stuff should be fairly obvious, if you run into issues or question about it, feel free to post the code you tried here to get some help.
There are also a lot of examples on this forums involving pax
As for
fbackup, nothing is stopping you to experiment a bit, doesn't it
Hope that clears things out
Regards
Peasant.