Fuel cut off switch. Iveco daily?

I need to install a switch to the fuel cut off switch as a security device on Iveco daily 35s12 2.3hpi.

Where is the fuel switch located and what wire do i need to put the switch in.

I was hoping i could remove one wire from the switch, run this to a hidden rocker switch then back to the fuel switch.

I would be greatful if anyone had a spare manual as I have not got one.