Ubuntu – I can get the Apple Magic Mouse to pair, but the mouse stays in discover mode

I've got a Magic Mouse, using an Asus Bluetooth dongle.

This is a description of trying it on Natty a few months ago on a Lenovo laptop with Unity, though trying again on Precise on a desktop with Gnome Shell gives me pretty much the same results. The mouse does actually work on Lucid, though I think scroll wasn't supported back then. I try to follow the instructions here:

https://help.ubuntu.com/community/AppleMagicMouse

Though the actual BT preferences wizard diverged slightly at step 6 back when I looked at these instructions for Natty.

• I bring up the BT preferences.
• I turn on my mouse, wait for it to start blinking.
• I click "Set up new device…".
• It finds my mouse.
• I click on PIN options and set it to 0000. (note that in Lucid, I don't do this, instead it comes up as a dialog as it's pairing, which does not happen here)
• I select it and click Forward.
• It goes through its process and says it's successfully connected.
• It's now listed as a device in the BT preferences window, but the mouse is still blinking, and doesn't move my cursor.
• There's an icon, I think implying "connected", that stays on until the mouse gives up on discovery mode and shuts off. (the same icon goes away when I click "disconnect" in the preferences window)

If I try the same thing, but leave the pin on "automatic", it does the same thing, except the "connected" icon only stays on for a second.

Any idea where to go from here?