Well, just off the top of my head, it should be either an autopilot which adjusts the attitude on the fly as the electric motor is thrusting, or it should provide a cue a la TransX so the Orbinaut can adjust the attitude himself.
The latter would be difficult in time accel, but not impossible, since the attitude, once you've broken free of the planet's SOI, will change rather slowly as you spiral out from or in towards the sun on the way to your destination planet.
The MFD would also have to alert the pilot that the turn-around time is approaching, so you know when to turn around and thrust backwards to slow down as you approach. It would be like using AGMFD in slow motion.
The hard part is the algorithm that drives all that. It has to be a numerical engine of some sort, which takes into account orbit planning and your ship's mass and engine parameters.