Hi Alvaro
Look at the WORKFLOW -> SETTINGS -> COORDINATE SYSTEMS if you set the proper OUTPUT coordinate system. Then when you export a model, you can select the exporting option.
As for the ORTHO data, please look at the ORTHO PROJECTION when the file is generated to check if you have a proper PROJECTION SYSTEM.
When everything is set properly, as mentioned above, and you still get these issues, look if you export the TWF files next to the ortho data. the TWF file specifies the COORDINATE SYSTEM, so it could be the GIS importer compatibility issue.
What particular GIS software are you using ?