If your are talking about the rear map lights. Yes it's possible because I have done it. You would need the enitre map light harness from the calais (get the connection too). The only thing you have to do is match the colours (I Think) by tapping the wires. Get a test light!
You would need a door wire which is a negative (tigger) and power (constant get it from the boot light) then ground. Join them up and it will work.