Comment 6 for bug 618838

The bluetooth pairing assistant is just terribly broken. It simply doesn't care if you select '0000' or whatever, it will always try its 6-digit pin.

This is what works for me with paring with my Magic Trackpad:

1) Try to pair with the "0000" pin option. It will fail with the 6-digit number. Restart the assistant.
2) Try to pair with the "automatic" pin option. It will fail with the 6-digit number. Restart the assistant.
3) Try to pair with the "0000" pin option again. This time, it will magically work.

This 3-step procedure works for me on Ubuntu 12.04 and 13.04.

Please tell me if it works for you.