Ok, so for your pump it just needs to be powered all the time, and it is done. If they did this part for you, then that is step one.
Next, you need to ground LEV at the ecu. Just have the wire come off the harness and ground it, unless you want to run it all the way to the working sensor.
Then you just need a standard 30amp relay and the 2 resistors to build the circuit like in the image. Just be careful to not fry anything. Make sure your doing the right wires etc... There is an ecu pin out in the st205 faq thread.