Just tested after installing your pakcage + restarting the device - the mouse connects ok, but the joystick is not working (same behavior as without your package).
one more thing i forgot to add and maybe will help analyzing this:
without the bt package (with extmou and extkbd uninstalled), when i press the DS3 button - it just connects to the device with no messages on the N900, but after the bt package is installed i get a dialog saying "accept connection with device? PLAYSTATION(R)3 Controller" with yes/no buttons.
pressing yes or no doesn't matter - it fails to connect and the dialog pops back again after a few seconds (beause the DS3 is still trying to connect).

I hope this helps.