Avoid Automatic Centering

Despite an object being moved from the center of the build plate, Astroprint does not seem to save it or slice it this way and the object always reverts to dead center of the bed. How can I slice the model so the object is printed somewhere other than center? The main reason for this is so I can use my printer in duplication or mirror mode to print using both extruders. This cannot be done when the object is dead center. Any thoughts would be appreciated.