As far as mountain lion is concerned regarding Time Machine. the error, i believe, is with OS X, Not QNAP FW. it appears that you cannot mount two shares of the same server with two user names.
I have my 419ii setup with one username and one main share that is mounted and stays on the desktop for access. when i try to get Time Machine to find the other, it'll find the drive, allow you to enter the username/pw. once the first backup takes place, the NAS is no longer accessible. my theory is that because my personal share (with a diff Username) is connected.
this is my work around:
1. disconnect all share
2. add a username with a quota (1tb was my choice)
3. add a share for that user
4. mount that share with the
afp://username:password@ip/newShareName5. during the initial backup, i ran this command: sudo chflags hidden "/Volumes/Time Machine Backups"
6. after completion of the backup, i unmounted the "newShareName", and remounted MY share, with MY username.
now when TM does it work, it just mounts the "Time Machine Backups", not the newShareName. it does so with Time Machine Backups hidden, so i never see it. and just continually backups. It has quota of 1TB. i honestly dont see the need for the "backup" application for time machine? this process is not transparent for the regular user, but i dont' want to keep fighting with the Time Machine app.
is there any other features that i'm missing from the time machine app?