I have a Geeetech I3-X printer and cannot place the start point at the center of the bed. The print is 182mm diameter which should fit on a 200x200 bed. The model is positioned at the middle of the bed in Repetier-Host. I slice with Slic3r and tried re-positioning it here but all the prints are off center when plotted and will not fit on the bed. Any suggestions ? Paul.