I've written a simple Python script using the Bluez (version 4.66) stack (thanks to http://shr-project.org/trac/wiki/Using) with this usage:
python connect.py MACADDRESS PIN MOUNTPOINT
Snippet code for connect.py is here. If the device is paired, it will be removed and unmounted.
Disconnection is as easy with:
python disconnect.py MACADDRESS MOUNTPOINT
Snippet code for disconnect.py is here.
Feel free to use the code also for other services, in this case my primary concern was to mount the file system.