Do you have any information concerning the MR2 pump wiring?
I found few other people doing this but did not find yet somebody with variable steering yet like you are doing.
I found this person that did a great job but I'm wondering if there is a way around of not having the ECU and all the components he is listing...
http://www.dsmtuners.com/forums/articles-suspension-brakes/415129-how-install-mr2-power-steering-pump.html
Greg