stupid alarm question

ok, i just had an alarm installed (sidewinder 5000ESP) and they did a horrible job - loose wires everywhere and they might as well have put the brain on top of the dash for all the more they "hid" it.

so today i tore apart my dash and taped all the wires up and reconnected a few that fell off when i moved the brain, then i hid it really well. the only problem is that now the shock sensor doesn't seem to work. does it have to be attached to a solid part of the car to work? or can i just suspend it with wire ties? or do i need to adjust the sensitivity? i know it sounds stupid, but i don't know how these things work.