After trying out kerunt's luggage, I got a set as well! They are very, very nice; fits perfectly on my mutarded bike without any modification (blinkers visible from 45' angle). Took a while to set everything up, but once setup is done, they can be mounted/dismounted in 30 seconds. Very sturdy!
2 buckles on passenger pegs (saddle bag)
2 buckles under tail (saddle bag)
2 bungee cords to passenger pegs (tail bag)
1 bungee cord under tail (tail bag)
tail bag also has 2 buckles on each side that clips into the saddle bags