New version makes a new icon for the "watcher".

So the procedure now is:
1. Pair your devices with the N900 via the Bluetooth menu.
2. Use the "BT HID Connect" icon to connect your devices properly (this will make the BT logo stay blue, the mouse and keyboard will work, incompletely)
3. Make sure your devices are disconnected, then start the "BT HID Watcher" icon to auto-configure your N900 when the devices connect.
4. Turn on your device, press a key or whatever you need to do, and then watch for the yellow banner on the N900 saying that you're connected. The mouse pointer should become visible for a mouse, and the keyboard should have numbers and special characters properly mapped.

Note that you may need to open the N900 keyboard and press a key to get the external keyboard working properly.