at the back of the power button there will be 2 contacts, solder some old pc fan wire or speaker cable e.t.c to both contacts and then you can mount a switch to those wires.
forget soldering to the ribbon and using single core cat5e :\
simplez
Cool thanks for the info, although i can't remember seeing the two contacts on there, the ribbon just slots in to a white plastic slot, inside there are 5 pin outputs.
I will have to check to see if I can see two pin outputs