electronic VNT control question

i see people on here buying the 1756's or other large turbos that come with electronic VNT actuators and converting them over to vacuum control. can someone hook up a boost controler to that and run it on a MK4 jetta or something with an ALH motor? i'm just asking what you would have to do to run it with the electronic actuator on a car that was not designed to do so from the factory.