Hi, sonshine -
Go to the 'Groups' tab in PoseRay. The controls there allow you to scale, rotate and translate the model (or just selected groups). You can also generate normals.
Click on the little plus sign in the lower left corner of the main window, and it'll bring up a separate proporty sheet. Select the 'Geometry' tab and you'll be able to see the results of any scaling operation; you can also use the data presented to center the object in X and Z about the origin, if desired.