It's a hell of a lot easier than that. Just enter:

in Terminal, and your network drives will show up when you go to pick a drive in Time Machine. All caveats about doing something that Apple doesn't seem to want you to do apply, though.

Wow - now that is exactly what I was looking for!

Agreed. The preference change makes this whole procedure not really needed anymore. I had thrown this all together pretty quickly after Leopard came out, and before the hidden preference was discovered.

One thing I haven't tested though is to see how the preference affects Leopards ability to see a share booting off the DVD for a complete restore. Using the method above, it showed up as long as I used Terminal to mount the disk first (mount_afp).

I have an iomega NAS server here, and when I tried the "unsupported = 1" prefs change the NAS volumes appeared in Time Machine but I systematically got an error in creating the backup files; on the contrary your longer step-by-step worked perfectly :-)

Apple may have added some multi-linked file support HFS+/AFP to get TimeMachine to work. (I don't know if directory hard links work before 10.5, for example.) If this is the case, you'd better be sure that the AFP server you're using supports this or you may get incomplete/invalid backups. One way around this is to use a disk image, but that may be much much much slower. (And at least on Intel 10.4 there's a pretty nasty memory leak with large disk images.)

Yes, hard linked directories work in 10.4. Not sure about 10.3, I haven't tried anything there.

If you're on 10.4, you can compile the gnu version of coreutils and together with rsync you can build a home-brew version of time machine.

This method forces a disk image to be created, as a sparsebundle. It seems Leopard does this automatically over a network, even when talking to another Leopard machine.

using an afp/hfs+ nas was exactly how i wanted to use time machine. i'd heard about other limitations of the code & this hint reveals another. that there's an unsupported workaround means that it shouldn't be too difficult for apple to make this an official method. i can understand their reluctance - difficult enough to warrant people's usb/firewire drives let alone a nas - but it'd be great if they'd make this an advanced configuration option for those of us willing to give it a go.

so how does one request this?

nope. that one just goes into a black hole (or if you're a young kid, you'll get a nastygram from apple legal telling you to bug out). apple is no worse than most firms - it's difficult to make a formal request for enhancement of many products ...

I tried this to a Buffalotech NAS using AFP. It kind of works, but not well at all.

Here's the problem I had: when your disk fills up and it goes to delete old backups it screws things up. It succeeds in deleting the old backups (unlike SMB shares) but you loose everything except the most recent backup from the GUI. They're still there on the disk (as far as I can tell). So be forewarned: at least on my AFP NAS this is not an acceptable solution.

(To test this you can make a sparsebundle in the Disk Utility with a small fixed size and name it the same as the one TM makes then tell it to backup just a folder (exclude everything else) and change the name of the folder until it fills up. You can then watch it delete backups and see if it actually works for you. After about 5 old backup deletions it stopped working in the GUI for me.)

It is possible for the time machine sparsebundle to get corrupted if you're backing up to an SMB share and you put your notebook to sleep.

The solution is here:

http://www.macosxhints.com/article.php?story=20081115172028293

This sets up a script that causes the backup volume to be safely ejected when you put the computer to sleep. Problem solved.