I have a Time Machine backup of my MacBook Pro pro that's encrypted and saved on a Synology DS212j NAS (OS X detected my NAS as a possible location to save my backup). Right now I'm on my MacBook Air. Is it possible to browse the MacBook Pro's encrypted backup on the NAS? All I see is a "sparsebundle" file. My MacBook Pro is currently being repaired so I don't have access to it.
If OS X detects the NAS as a possible backup destination, you should be able to option-right-click (hold option while right-clicking) the Time Machine icon in the menu bar, and select "Browse Other Backup Disks". The AFP mount should show up there and you should be able to browse it.
Alternately, just mount the sparsebundle. It works just like a .dmg. If double-clicking doesn't give you the option to type in the password and mount it, you can drag it into Disk Utility and mount it from there.