Hmmm....do you know which rev it is using for its Bluetooth Stack, is it a 2.0, 2.1, 3.0 or 4.0? I haven't tried anything but 3.0 (Bluetooth Notebook Mouse 5000) and 4.0 (the Wedge Mouse). Both reconnected automatically. You can also check in the Devices and Printers (Desktop Control Panel) and right click on the mouse and go to properties to see if there is the ability to reconnect automatically.
HTH,