Hello mauovernet,
Do you actually need to move the region's center to (0,0,0) or have the coordinate system origin be in the center of the bounding box (region), having the transformation applied to the reconstructed model?
For the latter case I suggest the following approach:
- enable Show Grid option in the Model menu,
- switch from Perspective to Orthographic representation (also through the Model Menu -> View Mode -> Perspective/Orthogrpahic option),
- use Predefined view options from the Model menu for better convenience of the next step,
- then in the Model view mode use Move Object tool to adjust model's location relatively to the shown grid - it's center (0,0,0) is marked by the X mark.
Once the center of the model is set up close to (0,0,0) point you can also use Rotate Object tool to adjust the model's orientation relatively to the grid (and therefore to the coordinate system axis).