Special Projects to access from program's menu on the right side - 

Help -> Vehicle allocation

Take English or German version of VehicleMapping.htm file and copy it to:

For Version 12.x.y
C:\Program Files (x86)\Offboard_Diagnostic_Information_System_Engineering\Manuals\

For Version 13.x.y and up
C:\ProgramData\Offboard_Diagnostic_Information_System_Engineering\Manuals\

by Fantomel :)
Enjoy