Open status-bar menu, click Bluetooth (also test if discoverable makesany difference), enable Bluetooth, click on Devices (or similar), click New, if it is not searching for new devices by itself. Start your headset in discovery mode (you should know, how to do it).
Good Luck

Mine works just as i expect it to (most of the time at least)


* N900 BT ON + Turn the headset ON while in range = It connects
* It is connected, then goes off range, then in range again = It connects
* It is connected and then i disconnect it via the N900 (via the button in the status menu) while leaving the headset on = It stays disconnected untill i tell either device to connect again (either using the BT "program" on the N900 or by doing the connect procedure on the headset, which for my model in specific can be either holding the acept/dismiss call button for a couple of seconds, or turing it off/on).



I said it works well most of the time 'cause every once in a while i need to toggle the BT radio on the N900 and/or cycle tthe headset itself in order to get the connection to work or else it looks like the devices aren't in range.