It's easy mate, I did mine last year when it started playing up, mine was a system 3. Just trace the datatool loom where it joins the main loom and you should find that most of the plain black alarm wires are soldered onto the bikes wires without the bikes wires actually being cut, just the insulation pulled back for soldering. On these I just cut off the black alarm wires and put new insulation on, a bit of self amalgamaging tape did the trick. On mine there was only two wires of the main loom that were cut and the alarm wiring soldered onto these, ignition and fuel pump if I remember right. Just reconnect these and Bob should be your uncle.
Hope this helps.